1955-1982 Pontiac V-8 Engines – Part 3

The 400 CID version of the Pontiac small journal V-8 was available beginning in 1967. In various performance configurations, it was the halo V-8 for the Pontiac GTO and Firebird.

Pontiac Small Journal V8s – Part Three: 400 and 350 CID

Small Crankshaft Journal (3.00″) Engines

Pontiac V8 engines are broken into two categories – small main journal and large main journal engines. All Pontiac engines have the same deck height except for the 1969 303 Trans Am engine and the short-lived 301 and 265 V8s of the early 80s. The early 287-370 CID engines used smaller diameter main journals, with the first two utilizing 2.5″ mains and the 347 and 370 CID using 2.623″ mains. The 301 and 265 reverted to the original 287 CID 2.5″ mains.

    • 400 CID – For 1967, Pontiac introduced the 400 CID V8. The “400” was a bored-out 389 CID with 4.120″ bore and the 389’s 3.75″ stroke, resulting in 400.4 CID. It replaced the 389 and remained in production through the 1979 model year.
    • 350 CID – The 350 CID V-8 was introduced in 1968 and replaced the 326, with not much more than a bore increase.

The large main journal (3.25″) engines were the 421, 428 and 455 V8s.

NOTE: Unless designated, specifications are for full size cars.

Engines are listed in the order of introduction by Pontiac.

400 CID V8 (1967-1976)

1967 400 CID V-8

In 1967, the cylinder head design was improved for all Pontiac engines. The valve angle was changed for better breathing. 1967 was the last year for the old closed chambered heads. This “670” head was a ’67-only casting, and the last PMD head to have a closed combustion chamber.

Pontiac went to open combustion chambered heads in ’68 to improve power, engine breathing and emissions. On all performance engines, the valve size was increased as well, to 2.11″ intake and 1.77″ exhaust valves. Low performance and 2-barrel carbureted applications received 1.96″ intake and 1.66″ exhaust valves and pressed in rocker arm studs.

The 3-2 barrel carburetor setup discontinued on GTOs beginning in 1967 as part of a GM edict that only the larger B-C body cars and Corvette could use multiple carburetors. Horsepower for the new 400 ranged from 265 in the “economy” 2-barrel 8.6:1 GTO engine all the way up to 360 for the Ram Air version.

The standard 1967 360 HP GTO engine is considered the “HO” and the optional, race-only version was called “Ram Air 400”. Though they were rated at the same horsepower, they were very different, with the RA 400 receiving a more radical cam and different, freer flowing cylinder heads.

1967 Pontiac 400 CID Engine Specifications
Click the tabs for specific engine information

Optional GTO 255 Horsepower  Economy V-8 – GTO , All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.6:1.
Horsepower: 255 @ 4400 RPM.
Torque: 397 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″.
Carburetor:  Rochester two-barrel  Model 7027060.

265 Horsepower  Economy V-8 – All Series , All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.6:1.
Horsepower: 265 @ 4600 RPM.
Torque: 397 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″.
Carburetor:  Rochester two-barrel  (manual transmission) Model 7027066; (automatic transmission) 7027060.

290 Horsepower  V-8 – All Series , Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 290 @ 4600 RPM.
Torque: 428 @ 2500 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″.
Carburetor:  Rochester two-barrel 7027060.

325 Horsepower  V-8 – Bonneville and Bonneville Wagon Series, Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 325 @ 4800 RPM.
Torque: 445 @ 2900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 283°, Exhaust 272°, Overlap 55°, Lift (intake) 0.407″; (exhaust) 0.412″.
Carburetor:  Carter AFB Four-barrel 4242S.

333 Horsepower  V-8 – All Series, Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 333 @ 5000 RPM.
Torque: 445 @ 3000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.407″; (exhaust) 0.411″.
Carburetor:  Carter AFB Four-barrel 4243S.

Optional GTO 335 Horsepower V-8 – GTO Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.125″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 335 @ 5000 RPM.
Torque: 441 @ 3400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7027263 or Carter AFB Four-barrel 4243S.

Optional GTO 335 Horsepower V-8 – GTO Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 335 @ 5000 RPM.
Torque: 441 @ 3400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7027262 or Carter AFB Four-barrel 4242S.

350 Horsepower  V-8 – Grand Prix, Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 350 @ 5000 RPM.
Torque: 440 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.407″; (exhaust) 0.411″.
Carburetor:  Carter AFB Four-barrel 4243S.

350 Horsepower  V-8 – Grand Prix, Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 350 @ 5000 RPM.
Torque: 440 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor:  Carter AFB Four-barrel 4242S.

Optional GTO 360 Horsepower HO V-8 – GTO , All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 360 @ 5100 RPM.
Torque: 438 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7027263; (automatic) 7027262.

Optional GTO 360 Horsepower Ram Air V-8 – GTO , All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 360 @ 5400 RPM.
Torque: 438 @ 3800 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7027263; (automatic) 7027262.

1968 400 CID V-8

The 400 base engines remained unchanged for 1968, except that the 400 was now available in the Firebird with three special HP ratings – 330 and 335 and 340 with the last two being Ram Air I and II engines. The Ram Air I engine was rated at 366 HP, though it was far more than 6 HP stouter than the 360 HP HO version. Late in the year the Ram Air II GTO engine replaced the Ram Air I and received a 370 HP rating, again far more stouter than the 4 HP upgrade. It received special round exhaust ports and taller intakes and a different manifold to match the heads (this was the same engine as the 340 HP Ram Air II in the Firebird).

1968 Pontiac 400 CID Engine Specifications
Click the tabs for specific engine information

Optional GTO 265 Horsepower  Economy V-8 – GTO , All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.6:1.
Horsepower: 265 @ 4600 RPM.
Torque: 397 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor:  Rochester two-barrel  Model 7028060.

265 Horsepower  Economy V-8 – All Full-Size Series , All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.6:1.
Horsepower: 265 @ 4600 RPM.
Torque: 397 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″.
Carburetor:  Rochester two-barrel 7028060.

290 Horsepower  V-8 – All Series , Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 290 @ 4600 RPM.
Torque: 428 @ 2500 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″.
Carburetor:  Rochester two-barrel 7028060.

290 Horsepower  V-8 – All Series, Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 290 @ 4600 RPM.
Torque: 428 @ 2500 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor:  Rochester two-barrel 7028066.

Optional Firebird 330 Horsepower V-8: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 330 @ 4800 RPM.
Torque: 430 @ 3300 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7028263; (automatic transmission) 7028268.

Optional Firebird 335 Horsepower HO V-8, Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 335 @ 5000 RPM.
Torque: 430 @ 3400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7028275; (automatic) 7028268.

Optional Firebird 335 Horsepower HO V-8, Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 335 @ 5000 RPM.
Torque: 430 @ 3400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7028275; (automatic) 7028268.

Optional Firebird 340 Horsepower Ram Air II V-8 – Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 340 @ 5300 RPM.
Torque: 430 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.
Carburetor: Rochester four-barrel  7028274.

Optional Firebird 340 Horsepower Ram Air II V-8 – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 340 @ 5300 RPM.
Torque: 430 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7028275.

340 Horsepower  V-8 – All Series, Except Grand Prix – Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 340 @ 4800 RPM.
Torque: 445 @ 2900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor: Rochester Four-barrel 7028262.

340 Horsepower  V-8 – All Series, Except Grand Prix – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 340 @ 4800 RPM.
Torque: 445 @ 2900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor: Rochester Four-barrel 7028263.

350 Horsepower  V-8 – Grand Prix – Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 350 @ 5000 RPM.
Torque: 445 @ 3000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor:  Carter AFB Four-barrel 4242S or Rochester 7028268.

350 Horsepower  V-8 – Grand Prix – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 350 @ 5000 RPM.
Torque: 445 @ 3000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester 7028263.

Optional GTO 350 Horsepower V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 350 @ 5000 RPM.
Torque: 445 @ 3000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7028263; (automatic transmission) 7028268.

Optional GTO 360 Horsepower HO V-8, – Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 360 @ 5100 RPM.
Torque: 438 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7028268.

Optional GTO 360 Horsepower HO V-8 – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 360 @ 5100 RPM.
Torque: 438 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″. 
Carburetor:  Rochester four-barrel 7028275.

Optional GTO 366 Horsepower Ram Air V-8 – Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 366 @ 5100 RPM.
Torque: 445 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″. 
Carburetor:  Rochester four-barrel 7028274.

Optional GTO 366 Horsepower Ram Air V-8 – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 366 @ 5100 RPM.
Torque: 445 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7028275.

Optional GTO 370 Horsepower Ram Air II V-8 – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 370 @ 5500 RPM.
Torque: 445 @ 3900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7028275.

Optional GTO 370 Horsepower Ram Air II V-8- Hydra-Matic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 370 @ 5500 RPM.
Torque: 445 @ 3900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7028274.

1969 400 CID V-8

In 1969, the standard “street” 400s were configured the same as 1968. The Ram Air I and II were discontinued and replaced with the Ram Air IV, a new Ram Air III, and an even more outlandish Ram Air V, rated at 375 HP and running “tunnel port” intake ports along with a mechanical cam with the same advertised duration as the Ram Air IV’s hydraulic camshaft. The rest of the Pontiac line remained the same.

1969 Pontiac 400 CID Engine Specifications
Click the tabs for specific engine information

Optional GTO 265 Horsepower  Economy V-8: GTO – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.6:1.
Horsepower: 265 @ 4600 RPM.
Torque: 397 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor: Rochester two-barrel  Model 7029060.

265 Horsepower  Economy V-8 – All Full-Size Series , All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.6:1.
Horsepower: 265 @ 4600 RPM.
Torque: 397 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing:: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″.
Carburetor:  Rochester two-barrel 7028060.

290 Horsepower  V-8 – All Series, Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 290 @ 4600 RPM.
Torque: 428 @ 2500 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″.
Carburetor: Rochester two-barrel 7028060.

290 Horsepower  V-8 – All Series, Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 290 @ 4600 RPM.
Torque: 428 @ 2500 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor:  Rochester two-barrel 7028066.

Optional Firebird 330 Horsepower V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 389 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 330 @ 4800 RPM.
Torque: 430 @ 3300 RPM.
Valve lifters: Hydraulic.
Camshaft timing:: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7029263; (automatic transmission) 7029268.

Optional Firebird 335 Horsepower HO V-8 – Automatic  Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 335 @ 5000 RPM.
Torque: 430 @ 3400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor: Rochester four-barrel 7029268.

Optional Firebird 335 Horsepower HO V-8 – Manual Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 335 @ 5000 RPM.
Torque: 430 @ 3400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″. Carburetor:  Rochester four-barrel  7029275;.

Optional Firebird Ram Air III V-8 – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 340 @ 5300 RPM.
Torque: 430 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7028270.

NOTE: The 400 Firebird HO could be Ram Air Equipped.  The only change was to install a specially calibrated Quadra-Jet 4-barrel.

Optional Firebird Ram Air III V-8 – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 335 @ 5300 RPM.
Torque: 430 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7028273.

NOTE: The 400 Firebird HO could be Ram Air III Equipped.  The only change was to install a specially calibrated Quadra-Jet 4-barrel.

Optional Firebird 345 Horsepower Ram Air IV V-8 – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 345 @ 5400 RPM.
Torque: 430 @ 3700 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.520″; (exhaust) 0.520″.
Carburetor:  Rochester four-barrel 7028270.

NOTE: Automatic transmission cars received a different carburetor.

Optional Firebird 345 Horsepower Ram Air IV V-8 – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 345 @ 5400 RPM.
Torque: 430 @ 3700 RPM.
Valve lifters: Hydraulic.
Camshaft timing:  Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.520″; (exhaust) 0.520″.
Carburetor:  Rochester Quadra-Jet four-barrel  7029273.

NOTE: Manual transmission cars received a different carburetor.

340 Horsepower  V-8 – Catalina & Executive Series Only Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 340 @ 4800 RPM.
Torque: 445 @ 2900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor: Rochester Four-barrel 7029262.

Optional GTO 350 Horsepower V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 350 @ 5000 RPM.
Torque: 445 @ 3000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7028263; (automatic transmission) 7028268.

Optional GTO 366 Horsepower Ram Air III V-8 – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 366 @ 5100 RPM.
Torque: 445 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.413″; (exhaust) 0.413″. 
Carburetor:  Rochester four-barrel 7028270.

Optional GTO 366 Horsepower Ram Air III V-8 Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 366 @ 5100 RPM.
Torque: 445 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing:  Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.414″; (exhaust) 0.413″
Carburetor:  Rochester four-barrel  7028273.

Optional GTO 370 Horsepower GTO Ram Air IV V-8 – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 370 @ 5500 RPM.
Torque: 445 @ 3900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.520″; (exhaust) 0.520″.
Carburetor:  Rochester four-barrel 7029270.

NOTE: Automatic transmission cars received a different carburetor.

Optional GTO 370 Horsepower GTO Ram Air IV V-8 – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 370 @ 5500 RPM.
Torque: 445 @ 3900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.520″; (exhaust) 0.520″.
Carburetor:  Rochester four-barrel 7029273.

NOTE: Manual transmission cars received a different carburetor.

375 Horsepower Ram Air V – Manual Transmission Only: Overhead valves. “Tunnel Port” Heads. Special intake manifold. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 11.00:1.
Horsepower: 375 @ 6000 RPM.
Torque: 445 @ 4000 RPM.
Valve lifters: Mechanical.
Camshaft timing: Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.490″; (exhaust) 0.498″.
Carburetor:  Holley four-barrel 4150-C #3923289.

NOTE: This engine was announced but never available to the public. See the Hot Rod Magazine Article HERE.

1970 400 CID V-8

With the lifting of the ban on 400 cubic inches, most of GM’s performance engines moved up to the new 455 cu. in limit, Pontiac did offer two 455s that year. But aside from that, the 400 still reigned supreme, with all the ram air cars still receiving the options of Ram Air III or IV. Except for dropping some of the HO 400s for 1970 and replacing them with 455s the 400 still had its active life as the mainstay of V8s in the Pontiac line.

1970 Pontiac 400 CID Engine Specifications
Click the tabs for specific engine information

Optional Tempest and Firebird 265 Horsepower  Economy V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.6:1.
Horsepower: 265 @ 4600 RPM.
Torque: 397 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor:  Rochester two-barrel  Model 7040060.

265 Horsepower  Economy V-8 – All Series – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.6:1.
Horsepower: 265 @ 4600 RPM.
Torque: 397 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″.
Carburetor:  Rochester two-barrel 7040060.

290 Horsepower  V-8 – All Series, Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.0:1.
Horsepower: 290 @ 4600 RPM.
Torque: 428 @ 2500 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″.
Carburetor:  Rochester two-barrel 7040060.

290 Horsepower  V-8 – All Series, Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.0:1.
Horsepower: 290 @ 4600 RPM.
Torque: 428 @ 2500 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor:  Rochester two-barrel 7040066.

Optional Firebird 330 Horsepower V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 389 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.25:1.
Horsepower: 330 @ 4800 RPM.
Torque: 430 @ 3300 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7040263; (automatic transmission) 7040264.

Optional Tempest 330 Horsepower V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 389 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.0:1.
Horsepower: 330 @ 4800 RPM.
Torque: 430 @ 3300 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°,  Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7029263; (automatic transmission) 7029268.

Optional Full Size 330 Horsepower V-8 – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 389 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.0:1.
Horsepower: 330 @ 4800 RPM.
Torque: 445 @ 2900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor:  Rochester four-barrel 7040264.

340 Horsepower  V-8 – Catalina & Executive Series Only – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 340 @ 4800 RPM.
Torque: 445 @ 2900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor: Rochester Four-barrel 7029262.

Optional Firebird 345 Horsepower Ram Air V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.5:1.
Horsepower: 345 @ 5000 RPM.
Torque: 430 @ 3400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: (manual trans) Intake 288°, Exhaust 302°, Overlap 87°, Lift (intake) 0.520″; (exhaust) 0.520″.
Carburetor:  Rochester four-barrel (manual transmission) 7040273 (automatic transmission) 7040270.

Grand Prix Standard 350 Horsepower V-8 Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 350 @ 5000 RPM.
Torque: 445 @ 3000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor:  Rochester four-barrel 7040264.

Grand Prix Standard 350 Horsepower V-8 – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 350 @ 5000 RPM.
Torque: 445 @ 3000 RPM.  
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7040263.

Optional GTO 350 Horsepower V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.25:1.
Horsepower: 350 @ 5000 RPM.
Torque: 445 @ 3000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel (manual transmission) 7040263; (automatic transmission) 7040264.

Optional GTO 366 Horsepower Ram Air III V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 366 @ 5100 RPM.
Torque: 445 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.413″; (exhaust) 0.414″.
Carburetor:  Rochester four-barrel (manual transmission) 7040273; (automatic) 7040270.

Optional GTO 370 Horsepower Ram Air IV V-8 – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 10.75:1.
Horsepower: 370 @ 5500 RPM.
Torque: 445 @ 3900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.520″; (exhaust) 0.520″.
Carburetor:  Rochester four-barrel (manual transmission) 7040273; (automatic) 7040270.

1971 400 CID V-8

Things changed radically in 1971, with the reduction of compression ratios to meet the soon to be instituted unleaded gas requirements. Only two types of 400s were offered, and they were equipped with 2-barrel and 4-barrel carburetors and 8.2:1 compression ratio. The performance banner would now be carried by the 455.

1971 Pontiac 400 CID Engine Specifications
Click the tabs for specific engine information

265 Horsepower  Economy V-8. All Series Including GTO  – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.2:1.
Horsepower: 265 @ 4400 RPM.
Torque: 400 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor:  Rochester two-barrel 7041060.

265 Horsepower  Economy V-8.  All Series Including GTO – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.2:1.
Horsepower: 265 @ 4400 RPM.
Torque: 400 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester two-barrel 7041060.

300 Horsepower  V-8. All Series Including GTO – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.2:1
Horsepower: 300 @ 4800 RPM.
Torque: 400 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester Four-barrel 7041264.

300 Horsepower  V-8. All Series Including GTO – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.2:1.
Horsepower: 300 @ 4800 RPM.
Torque: 400 @ 3600 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester Four-barrel 7041263.

1972 400 CID V-8

For 1972, a 4-barrel 400 returned with a weak 250 SAE Net hp rating, but the 400 still only had two offerings – 2 and 4-barrel; otherwise they were much the same.  NOTE: All engine horsepower was now given in SAE NET, meaning it was computed with all attachments such as alternator,  water pump, fans, belts and normal engine headers.

1972 Pontiac 400 CID Engine Specifications – All Horsepower Rating are now SAE Net
Click the tabs for specific engine information

175 Horsepower  L65 400 CID V-8. All Series Including GTO – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.2:1.
Horsepower: 175 @ 4000 RPM.
Torque: 310 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor:  Rochester two-barrel 7042060.
Exhaust: Single.

200 Horsepower L65 400 CID V-8. All Series Including GTO – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.2:1.
Horsepower: 200 @ 4000 RPM.
Torque: 325 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor:  Rochester two-barrel 7042060.
Exhaust: Dual.

200 Horsepower L78  V-8. All Series Including GTO – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.2:1.
Horsepower: 200 @ 4000 RPM.
Torque: 295 @ 2900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7042263.
Exhaust: Single.

250 Horsepower L78  V-8. All Series Including GTO – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.2:1.
Horsepower: 250 @ 4400 RPM.
Torque: 325 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor:  Rochester four-barrel 7042263.
Exhaust: Dual.

1973 400 CID V-8

Three 400s were offered in 1973 but they were mostly available to pull around bigger cars seeking a bit better fuel mileage. The Lemans/Grand Am/Firebird lines did have a 230 HP 4-barrel unique to their cars. The GTO was a trim option on the LeMans only – no special 400 CID engine.

1973 Pontiac 400 CID Engine Specifications – All Rating are now SAE Net
Click the tabs for specific engine information

170 Horsepower  L65 400 CID V-8. All Series Including GTO – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 170 @ 3600 RPM.
Torque: 320 @ 2000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 55°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor: Rochester two-barrel 7043060.
Exhaust: Single.

185 Horsepower L65 400 CID V-8. All Series Including GTO – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 185 @ 4000 RPM.
Torque: 320 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 55°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor: Rochester two-barrel 7043061.
Exhaust: Dual.

185 Horsepower L65 400 CID V-8. All Series Including GTO – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 185 @ 4000 RPM.
Torque: 320 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 55°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor: Rochester two-barrel 7043061.
Exhaust: Dual.

230 Horsepower L78  V-8. All Mid-Size, GTO & Firebird Series Excludes, Full-Size – Manual Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 200 @ 4000 RPM.
Torque: 325 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor: Rochester four-barrel 7043263.
Exhaust: Dual.

230 Horsepower L78  V-8. All Series Including GTO – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 200 @ 4000 RPM.
Torque: 325 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.415″.
Carburetor:  Rochester four-barrel 7043264.
Exhaust: Dual.

1974 400 CID V-8

Two 400s were offered in 1974, but they were mostly available to pull around bigger cars seeking a bit better fuel mileage. In 1974 horsepower changed slightly. The newly released GTO was a Pontiac X body Ventura and its powerplant was a 350 CID V-8 with 200 HP.

1974 Pontiac 400 CID Engine Specifications – All rating are now SAE Net
Click the tabs for specific engine information

175 Horsepower  L65 400 CID V-8. All Series Excluding GTO – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 170 @ 3600 RPM.
Torque: 320 @ 2000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 55°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor:  Rochester two-barrel (Firebird/LeMans/Grand Am) 7044066; (Full Size Station Wagon) 70440670. (California) 7044067.
Exhaust: Single.

190 Horsepower  L65 400 CID V-8. Firebird & Mid-Size Only. Excludes GTO – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings. Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 190 @ 4000 RPM.
Torque: 320 @ 2000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 55°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor:  Rochester two-barrel 7044066.
Exhaust: Dual.

200 Horsepower L78  V-8. Full Size Cars Only – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 200 @ 4000 RPM.
Torque: 325 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.415″.
Carburetor:  Rochester four-barrel 7044266, (altitude calibration model) 7044274. Not Available in California.
Exhaust: Single.

1975-1979 400 CID V-8

Though the 400 would soldier on in the All lines and would continue to receive a 4 barrel carburetor, it was basically a pedestrian engine, though for the period, perky. In 1980, the 400 was quietly dropped. NOTE: Going forward, all engines would receive a single exhaust and a catalytic converter.

1975-1979 Pontiac 400 CID Engine Specifications
Click the tabs for specific engine information
NOTE: Specifications Shown for 1975 Only

170 Horsepower  L65 400 CID V-8. Full Size Car – Automatic Transmission: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 7.6:1. Horsepower: 170 @ 4000 RPM. Torque: 320 @ 2000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 282°, Overlap 59°, Lift (intake) 0.377″; (exhaust) 0.415″.
Carburetor: Rochester two-barrel 7045160; Not Available in California
Exhaust: Single.

185 Horsepower V-8. Firebird – All Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 185 @ 3600 RPM.
Torque: 325 @ 3200 RPM. 
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.415″. Carburetor: 
Rochester four-barrel (manual transmission) 7045269 Not Available in California; (automatic transmission) 7045564.

185 Horsepower V-8. Mid-Size Car – Automatic Transmissions: Overhead valves. Cast iron block. Five main bearings.
Displacement: 400 CID.
Bore and stroke: 4.120″ x 3.750″.
Compression ratio: 8.0:1.
Horsepower: 185 @ 3600 RPM.
Torque: 325 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.415″.
Carburetor: Rochester four-barrel 7045564.
Exhaust: Single.

350 CID V8 (1968-1976)

In 1968 the 326 CID V-8 was replaced by the 350 CID engine, which used a 3.88″ bore and 3.75″ stroke for a total displacement of 354.71 cu in although it was called a 350.

1968 350 CID V-8

This engine was offered in both 2-barrel and 4-barrel variations similar to the previous 326 engine. In 1968, an “HO” option was available in the Tempest and Firebird models that was rated at 320 HP.

1968 Pontiac 350 CID Engine Specifications
Click the tabs for specific engine information

Firebird & Tempest Base V-8 – All Transmissions: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.8750″ x 3.75″
Compression ratio: 9.2:1.
Horsepower: 265 @ 4600 RPM.
Torque: 355 @ 2800 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor: Rochester 2-barrel (manual transmission) 7028071 (automatic) 7028062.

Firebird & Tempest HO 350 V-8 – Automatic Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.875″ x 3.75″
Compression ratio: 10.5:1.
Horsepower: 320 @ 5100 RPM.
Torque: 359 @ 2900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor: Rochester  7028266.

Firebird & Tempest HO 350 V-8 – Manual Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.875″ x 3.75″
Compression ratio: 10.5:1.
Horsepower: 320 @ 5100 RPM.
Torque: 359 @ 2900 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor: Rochester 7028269.

1969 350 CID V-8

This engine was also offered in 1969 along with a second HO version. The later 350 HO was rated at 330 HP in the Tempest 325 in the Firebird, and was equipped with the 400 CID large valve heads (#48 with 2.11″ intake and 1.77″ exhaust) and the 400 Ram Air camshaft (#068) in the manual transmission Tempest.

1969 Pontiac 350 CID Engine Specifications
Click the tabs for specific engine information

Firebird & Tempest Base V-8 – All Transmissions: Cast Iron Block. Five main bearings. 
Displacement: 350 CID.
Bore and stroke: 3.8750″ x 3.75″
Compression ratio: 9.2:1.
Horsepower: 265 @ 4600 RPM.
Torque: 355 @ 2800 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor: Rochester 2-barrel (manual transmission) 7028071 (automatic) 7029062.

Firebird HO 350 V-8 – Automatic Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.8750″ x 3.75″
Compression ratio: 10.5:1.
Horsepower: 325 @ 5100 RPM.
Torque: 380 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing:  Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor: Rochester  7029268.

Firebird HO 350 V-8 – Manual Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.8750″ x 3.75″
Compression ratio: 10.5:1.
Horsepower: 325 @ 5100 RPM.
Torque: 380 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.
Carburetor: Rochester 7029263.

Tempest HO 350 V-8 – Automatic Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.8750″ x 3.75″
Compression ratio: 10.5:1.
Horsepower: 330 @ 5100 RPM.
Torque: 380 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing:  Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.
Carburetor: Rochester  7029268.

Firebird HO 350 V-8 – Manual Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.8750″ x 3.75″
Compression ratio: 10.5:1.
Horsepower: 325 @ 5100 RPM.
Torque: 380 @ 3200 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.414″; (exhaust) 0.413″.
Carburetor: Rochester 7029263.

1970 350 CID V-8

In 1970 the 350 returned to its pedestrian roots, being offered only as a two-barrel. with the 1.96″/1.66″ valves – rated at 255 hp. It was, however offered in the full size car.

1970 Pontiac 350 CID Engine Specifications
Click the tabs for specific engine information

350 Base V-8 – All Series All Transmissions: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 8.8:1.
Horsepower: 255 @ 4600 RPM.
Torque: 355 @ 2800 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor: Rochester 2-barrel (manual transmission) 7040071 (automatic) 7040062.

1971-1976 350 CID V-8

The 350 was issued in various forms from 1971-1976, but only in 2-barrel form and with ratings from 150 to 175 HP SAE net. In 1975 it made a brief appearance as a 4-barrel option. The 350 disappeared from the lineup after 1976.

1971-1976 Pontiac 350 CID Engine Specifications – All rating after 1971 are now SAE Net
Click the tabs for specific engine information

350 V-8 – All Series – Automatic Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 8.0:1.
Horsepower: 250 @ 4400 RPM.
Torque: 350 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor: Rochester 2-barrel (all) 7041062

Base V-8 – All Series – Manual Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 8.0:1.
Horsepower: 250 @ 4400
RPM. Torque: 350 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor: Rochester 2-barrel (all) 7041171.

350 V-8 – Mid-Size & Firebird – Manual Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 8.0:1.
Horsepower: (single exhaust) 160 @ 4400 RPM. Torque: 270 @ 2000 RPM;
Horsepower: (dual exhaust) 175 @ 4400 RPM. Torque: 275 @ 2000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor: Carter 2-barrel 488062.

Base V-8 – All Series Except Full Size – Automatic Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 8.0:1.
Horsepower: (single exhaust) 160 @ 4400 RPM. Torque: 270 @ 2000 RPM;
Horsepower: (dual exhaust) 175 @ 4400 RPM. Torque: 275 @ 2000 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″.
Carburetor: Rochester 2-barrel 7042062.

350 V-8 All Series – Automatic Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 8.0:1.
Horsepower: (single exhaust) 150 @ 4000 RPM. Torque: 270 @ 2000 RPM;
Horsepower: (dual exhaust) 175 @ 4400 RPM. Torque: 280 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor: Rochester 2-barrel (Full Size) 7043073,California 7043063; (Firebird & Mid-Size) 7043062 California 7043063; (Ventura) 7043062 California 7043362.

350 V-8 – All Series Except Full Size – Manual Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 8.0:1.
Horsepower: (single exhaust) 150 @ 4000 RPM. Torque: 270 @ 2000 RPM.
Horsepower: (dual exhaust) 175 @ 4400 RPM. Torque: 280 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″.
Carburetor: Rochester 2-barrel 7043071.

350 V-8 Ventura, Firebird & Mid-Size Series Only – All Transmissions: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 7.6:1.
Horsepower: (single exhaust) 155 @ 3600 RPM. Torque: 270 @ 2000 RPM;
Horsepower: (dual exhaust) 170 @ 4000 RPM. Torque: 280 @ 2400 RPM.
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor: Rochester 2-barrel (Firebird & Mid-Size Automatic) 7043062 California 7043063; (Ventura Automatic) 7043062 California 7043362.  (Firebird & Mid-Size manual) 7043071 Not Available in California; (Ventura manual) 7043071 Not Available in California.

350 V-8 Ventura, Firebird & Mid-Size Series – Automatic Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 7.6:1.
Horsepower: (single exhaust only) 155 @ 3600 RPM. Torque: 270 @ 2000 RPM;
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor: Rochester 2-barrel  7045171 Not Available in California.

350 V-8 Ventura, Firebird & Mid-Size Series – All Transmissions: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 7.6:1.
Horsepower: (single exhaust only) 175 @ 4000 RPM. Torque: 270 @ 2000 RPM;
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor: Rochester 4-barrel  (manual transmission) 7045269 Not Available in California; (automatic transmission) 7045268; California 7045568.

350 V-8 Ventura, Firebird & Mid-Size Series – Automatic Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 7.6:1.
Horsepower: (single exhaust only) 160 @ 4000 RPM. Torque: 280 @ 2000 RPM;
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor: Rochester 2-barrel  17056171

350 V-8 California Only: Ventura, Firebird & Mid-Size Series – Automatic Transmission: Cast Iron Block. Five main bearings.
Displacement: 350 CID.
Bore and stroke: 3.750″ x 3.75″
Compression ratio: 7.6:1.
Horsepower: (single exhaust only) 165 @ 4000 RPM. Torque: 260 @ 2400 RPM;
Valve lifters: Hydraulic.
Camshaft timing: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″.
Carburetor: Rochester 4-barrel 17056568 California Only

303 CID Trans Am V8 (1969)

In 1969, Pontiac unveiled its Trans Am model Firebird, and since racing rules required a sub-305 CID engine, Pontiac unveiled the 303 for racing models only, never available to the public. Bore and stroke were 4.125″ x 2.8125″, for 300.7 cu in . It was rated at 475 hp.

By the time this engine was ready, Pontiac had agreed not to compete in Trans Am and per GM headquarters.  No engines were ever released to the public. We have a Motor Trend magazine test of a Firebird equipped with this engine HERE.

Tran Am Experimental V-8 – Manual Transmission Only: Cast Iron Block. Five main bearings.
Displacement: 303 CID.
Bore and stroke: 4.125″ x 2.84″
Compression ratio: 11.0:1.
Horsepower: 475 @ 5600 RPM.
Torque: 395 @ 4200 RPM.
Valve lifters: Mechanical.
Camshaft timing: Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.490″; (exhaust) 0.498″. NOTE: Various camshafts were tried – this is the one example known.
Carburetor: Holley 4-barrel  #3923289

The Last Small Journal V-8 Engines

301 CID V8 (1977-1981) 

@ 4000   301 CID Naturally Aspirated

The 301 was offered from 1977 to 1981 and also installed in other GM cars during those years. The 301 had a 4.00″ bore and 3.00″ stroke for 301.6 cu in. The 301 block was based in part on designs for the “short deck” 303 CID engine designed for the Trans Am series, it had a shorter deck than the big V8, and used thin-wall castings to reduce weight. The crankshafts were also unique in the fact that they featured only two counter weights instead of the usual five, plus lightened connecting rod journals.

This lighter weight design was less than the Chevrolet small-block V-8. Power output ranged from 135 HP to 170 HP. The heads were a completely new design featuring siamesed intake ports. The short-deck block and different intake ports also required the design of a new intake manifold. The Pontiac 301 EC (Electronic Controls) version offered in 1981 produced 150 HP @ 4000 RPM and 245 ft. lbs. of torque 2000 RPM.

   301 CID Turbo

The 301 CID engine was also offered in Turbocharged form in 1980 and was rated at 210 HP @ 4000 rpm and 345 ft. lbs. @ 2000 RPM. The 1981 301 Turbo gained the electronic controls with an O2 sensor, feedback ECM and E4ME Quadra-Jet providing a slight reduction in output to 200 HP @ 4000 RPM and 340 ft. lbs. of torque @ 2000 RPM.

The 301 Turbo was unique in that it had a beefier block than the ’77-’79 301 CID engines (which carried on in the non turbo versions in 1980 and 1981), a very mild camshaft with 0.350″ lift and 250 degrees gross duration. A 60 psi oil pump was fitted to ensure adequate oil to the oil cooled Garrett TBO-305 Turbocharger It also featured a rolled fillet crankshaft, and a fully baffled oil pan.

The Turbo had a specific 800 CFM Quadra-Jet carburetor. This carburetor had extra-rich “DX” secondary metering rods and a remote vacuum source for the primary metering rod enrichment circuit to allow the Power Enrichment Vacuum Regulator (PEVR) to release the primary metering rods to move to the up position (enrichment) anytime during boosted conditions. This was to ensure there was enough fuel to cool the cast pistons. Boost was waste gate limited to 9 psi.

A THM-350 non-lockup automatic transmission was used in 1980 vehicles and a TH-350C lockup was installed in 1981 versions. The rear axle used 3.08 gearing. The 301 Turbo was limited to Trans Am and Formula Firebird production only.

Although it was much different than the original 1955-vintage Pontiac V-8 powerplant, the 301 has the distinction of being the last true Pontiac V-8 engine as Pontiac ceased V8 production on April 1, 1981.

265 CID V8 (1980-1981)

Based on the same short-deck block as the 301, the 265 was offered in 1980 and 1981 only, and featured a smaller bore of 3.75″, but the same 3.00″ stroke of the 301 for 265.1 cu in. In 1980 it produced 120 HP @ 4000 RPM and 210 ft. lbs. of torque @ 1600 RPM, and in 1981 120 HP @ 4000 RPM and 205 ft. lbs. of torque @ 2000 RPM.

When production ceased on the 265 and 301, Pontiac-specific V8 engines ceased to be.

Learn About the Pontiac Small Journal V-8 Part 1
Learn About the Pontiac Small Journal V-8 Part 2
Learn About the Pontiac Large Journal V-8
Learn More! View Our Pontiac Fact Sheets

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