1955-1982 Pontiac V-8s – 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.

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.

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

    • 400 CID – For 1967, Pontiac introduced the 400 CID V8. The “400” was a bored-out 389 CID with 4.1225″ 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.

Engines are listed in the order of introduction.

400 CID V8 (1967-1976)

1967

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 ’67 to improve power, engine breathing and emissions. On all performance engines, the valve size increased as well, to 2.11″ intake and 1.77″ exhaust valves. Low performance and 2bbl applications got 1.96″ intake and 1.66″ exhaust valves and pressed in rocker arm studs.

The 3-2 barrel setup disappeared on GTOs for 1967 as part of a GM edict that only B-C body 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.6:1. Horsepower: 255 @ 4400 RPM. Torque: 397 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.6:1. Horsepower: 265 @ 4600 RPM. Torque: 397 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 290 @ 4600 RPM. Torque: 428 @ 2500 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 325 @ 4800 RPM. Torque: 445 @ 2900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 333 @ 5000 RPM. Torque: 445 @ 3000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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, Manual Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 350 @ 5000 RPM. Torque: 440 @ 3200 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 350 @ 5000 RPM. Torque: 440 @ 3200 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″. Carburetor:  Carter AFB Four-barrel 4242S.

Optional GTO 335 Horsepower V-8 – GTO Automatic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 335 @ 5000 RPM. Torque: 441 @ 3400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.413″. Carburetor:  Rochester four-barrel 7027262 or Carter AFB Four-barrel 4242S.

Optional GTO 335 Horsepower V-8 – GTO Manual Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 335 @ 5000 RPM. Torque: 441 @ 3400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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 360 Horsepower HO V-8 – GTO , All Transmissions: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 360 @ 5100 RPM. Torque: 438 @ 3600 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 360 @ 5400 RPM. Torque: 438 @ 3800 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.413″. Carburetor:  Rochester four-barrel (manual transmission) 7027263; (automatic) 7027262.

1968

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 Ram Air I and II engines. The Ram Air II GTO engine replaced the Ram Air I and received a 366 hp rating, though it was far more than 6 hp stouter than the 360 hp HO. It received special round exhaust ports and taller intakes and a different manifold to match the heads. Later the Ram Air IV was released, and this was an even more special animal, with a special aluminum semi-high rise intake, and heads and a radical 308/320 cam.

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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.6:1. Horsepower: 265 @ 4600 RPM. Torque: 397 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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 Series , All Transmissions: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.6:1. Horsepower: 265 @ 4600 RPM. Torque: 397 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 290 @ 4600 RPM. Torque: 428 @ 2500 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 290 @ 4600 RPM. Torque: 428 @ 2500 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 389 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 330 @ 4800 RPM. Torque: 430 @ 3300 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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, All Transmissions: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 335 @ 5000 RPM. Torque: 430 @ 3400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration:

  • (manual trans) Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.
  • (automatic trans) Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.

Carburetor:  Rochester four-barrel (manual transmission) 7028275; (automatic) 7028268.

Optional Firebird 340 Horsepower Ram Air V-8: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 340 @ 5300 RPM. Torque: 430 @ 3600 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration:

  • (manual trans) Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.413″.
  • (auto trans) Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.

Carburetor:  Rochester four-barrel (manual transmission) 7028275; (automatic) 7028274.

340 Horsepower  V-8 – All Series, Except Grand Prix Manual Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 340 @ 4800 RPM. Torque: 445 @ 2900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.414″. Carburetor: Rochester Four-barrel 7028263.

340 Horsepower  V-8 – All Series, Except Grand Prix Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 340 @ 4800 RPM. Torque: 445 @ 2900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″. Carburetor: Rochester Four-barrel 7028262.

350 Horsepower  V-8 – Grand Prix, Manual Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 350 @ 5000 RPM. Torque: 445 @ 3000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″. Carburetor:  Rochester 7028263.

350 Horsepower  V-8 – Grand Prix, Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 350 @ 5000 RPM. Torque: 445 @ 3000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″. Carburetor:  Carter AFB Four-barrel 4242S or Rochester 7028268.

Optional GTO 350 Horsepower V-8: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 350 @ 5000 RPM. Torque: 445 @ 3000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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, All Transmissions: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 360 @ 5100 RPM. Torque: 438 @ 3600 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration:

  • (manual trans) Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.
  • (automatic trans) Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.

Carburetor:  Rochester four-barrel (manual transmission) 7028275; (automatic) 7028268.

Optional GTO 366 Horsepower Ram Air V-8: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 366 @ 5100 RPM. Torque: 445 @ 3600 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration:

  • (manual trans) Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.413″.
  • (auto trans) Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.

Carburetor:  Rochester four-barrel (manual transmission) 7028275; (automatic) 7028274.

Optional GTO 370 Horsepower Ram Air IV V-8: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 370 @ 5500 RPM. Torque: 445 @ 3900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration:

  • (manual trans) Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.413″.
  • (auto trans) Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.

Carburetor:  Rochester four-barrel (manual transmission) 7028275; (automatic) 7028274.

1969

In 1969, the standard “street” 400s configured the same as 1968. The Ram Air I and II were discontinued and replaced with the Ram Air IV from last year, 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.6:1. Horsepower: 265 @ 4600 RPM. Torque: 397 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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 Series , All Transmissions: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.6:1. Horsepower: 265 @ 4600 RPM. Torque: 397 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 290 @ 4600 RPM. Torque: 428 @ 2500 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 290 @ 4600 RPM. Torque: 428 @ 2500 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 389 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 330 @ 4800 RPM. Torque: 430 @ 3300 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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, All Transmissions: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 335 @ 5000 RPM. Torque: 430 @ 3400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration:

  • (manual trans) Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.414″; (exhaust) 0.413″.
  • (automatic trans) Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″.

Carburetor:  Rochester four-barrel (manual transmission) 7029275; (automatic) 7029268. With Ram Air: Rochester four-barrel (manual transmission) 7028273 (automatic transmission) 7028270).

Optional Firebird 345 Horsepower Ram Air IV V-8: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 345 @ 5400 RPM. Torque: 430 @ 3700 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: (manual trans) Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.520″; (exhaust) 0.520″. Carburetor:  Rochester four-barrel (manual transmission) 7028273 (automatic transmission) 7028270).

340 Horsepower  V-8 – Catalina & Executive Series Only Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 340 @ 4800 RPM. Torque: 445 @ 2900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″. Carburetor: Rochester Four-barrel 7029262.

Optional GTO 350 Horsepower V-8: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 350 @ 5000 RPM. Torque: 445 @ 3000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 366 @ 5100 RPM. Torque: 445 @ 3600 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration:

  • (manual trans) Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.414″; (exhaust) 0.413″.
  • (auto trans) Intake 288°, Exhaust 302°, Overlap 63°, Lift (intake) 0.413″; (exhaust) 0.413″.

Carburetor:  Rochester four-barrel (manual transmission) 7028273; (automatic) 7028270.

Optional GTO 370 Horsepower Ram Air IV V-8: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 370 @ 5500 RPM. Torque: 445 @ 3900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.520″; (exhaust) 0.520″. Carburetor:  Rochester four-barrel (manual transmission) 7029273; (automatic) 7029270.

1970

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 an active life as the mainstay of V8s in the Pontiac line.

1970 Pontiac 400 CID Engine Specifications
Click the tabs for specific engine information
NOTE: Engines are  for Full-Size unless otherwise noted.

Optional Tempest and Firebird 265 Horsepower  Economy V-8, All Transmissions: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.6:1. Horsepower: 265 @ 4600 RPM. Torque: 397 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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 , Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.6:1. Horsepower: 265 @ 4600 RPM. Torque: 397 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″. Carburetor:  Rochester two-barrel 7040060.

290 Horsepower  V-8 – All Series, Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.0:1. Horsepower: 290 @ 4600 RPM. Torque: 428 @ 2500 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.375″; (exhaust) 0.410″. Carburetor:  Rochester two-barrel 7040060.

290 Horsepower  V-8 – All Series, Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.0:1. Horsepower: 290 @ 4600 RPM. Torque: 428 @ 2500 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″. Carburetor:  Rochester two-barrel 7040066.

Optional Firebird 330 Horsepower V-8: Overhead valves. Cast iron block. Displacement: 389 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.25:1. Horsepower: 330 @ 4800 RPM. Torque: 430 @ 3300 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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: Overhead valves. Cast iron block. Displacement: 389 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.0:1. Horsepower: 330 @ 4800 RPM. Torque: 430 @ 3300 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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 Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 389 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.0:1. Horsepower: 330 @ 4800 RPM. Torque: 445 @ 2900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″. Carburetor:  Rochester four-barrel 7040264.

Optional Firebird 345 Horsepower Ram Air V-8: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 345 @ 5000 RPM. Torque: 430 @ 3400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: (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.

340 Horsepower  V-8 – Catalina & Executive Series Only Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.5:1. Horsepower: 340 @ 4800 RPM. Torque: 445 @ 2900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″. Carburetor: Rochester Four-barrel 7029262.

Grand Prix Standard 350 Horsepower V-8 Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 350 @ 5000 RPM. Torque: 445 @ 3000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 350 @ 5000 RPM. Torque: 445 @ 3000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″. Carburetor:  Rochester four-barrel 7040263.

Optional GTO 350 Horsepower V-8: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.25:1. Horsepower: 350 @ 5000 RPM. Torque: 445 @ 3000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 366 @ 5100 RPM. Torque: 445 @ 3600 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 10.75:1. Horsepower: 370 @ 5500 RPM. Torque: 445 @ 3900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 308°, Exhaust 320°, Overlap 87°, Lift (intake) 0.520″; (exhaust) 0.520″. Carburetor:  Rochester four-barrel (manual transmission) 7040273; (automatic) 7040270.

1971

Things changed radically in 1971, with the reduction of compression ratios to meet the soon to be instituted unleaded gas requirements. Only two 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.

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

265 Horsepower  Economy V-8 – All Series Including GTO , Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.2:1. Horsepower: 265 @ 4400 RPM. Torque: 400 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.2:1. Horsepower: 265 @ 4400 RPM. Torque: 400 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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, Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8:2. Horsepower: 300 @ 4800 RPM. Torque: 400 @ 3600 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: 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. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8:2. Horsepower: 300 @ 4800 RPM. Torque: 400 @ 3600 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″. Carburetor:  Rochester Four-barrel 7041263.

1972

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.

1972 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 Including GTO , Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.2:1. Horsepower: 175 @ 4000 RPM. Torque: 310 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″. Carburetor:  Rochester two-barrel 7042060. Single Exhaust.

200 Horsepower L65 400 CID V-8 – All Series Including GTO , Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.2:1. Horsepower: 200 @ 4000 RPM. Torque: 325 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 51°, Lift (intake) 0.377″; (exhaust) 0.413″. Carburetor:  Rochester two-barrel 7042060. Dual Exhaust.

200 Horsepower L78  V-8 – All Series Including GTO, Manual Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.2:1. Horsepower: 200 @ 4000 RPM. Torque: 295 @ 2900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″. Carburetor:  Rochester four-barrel 7042263. Single Exhaust

250 Horsepower L78  V-8 – All Series Including GTO, Manual Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.2:1. Horsepower: 250 @ 4400 RPM. Torque: 325 @ 3200 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″. Carburetor:  Rochester four-barrel 7042263. Dual Exhaust

1973-1974

Two 400s were offered in 1973 but they were mostly available to pull around bigger cars seeking a bit better fuel mileage. The newly released GTO was a Pontiac X body Ventura and its powerplant was a 350 with 200 hp.

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 Excluding GTO , Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.0:1. Horsepower: 170 @ 3600 RPM. Torque: 320 @ 2000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 55°, Lift (intake) 0.377″; (exhaust) 0.413″. Carburetor:  Rochester two-barrel 7043060. Single Exhaust.

185 Horsepower L65 400 CID V-8 – All Series Excluding GTO , Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.0:1. Horsepower: 185 @ 4000 RPM. Torque: 320 @ 2400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 55°, Lift (intake) 0.377″; (exhaust) 0.413″. Carburetor:  Rochester two-barrel 7043061. Dual Exhaust.

230 Horsepower L78  V-8 – All Series Including GTO, Manual Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.2:1. Horsepower: 200 @ 4000 RPM. Torque: 325 @ 3200 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″. Carburetor:  Rochester four-barrel 7043263. Dual Exhaust

230 Horsepower L78  V-8 – All Series Including GTO, Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.2:1. Horsepower: 200 @ 4000 RPM. Torque: 325 @ 3200 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.415″. Carburetor:  Rochester four-barrel 7043264. Dual Exhaust

1974

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.

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, Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.0:1. Horsepower: 170 @ 3600 RPM. Torque: 320 @ 2000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 55°, Lift (intake) 0.377″; (exhaust) 0.413″. Carburetor:  Rochester two-barrel 7044066; (Full Size Station Wagon) 70440670. (California) 7044067. Single Exhaust.

200 Horsepower L78  V-8 – All Series, Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.0:1. Horsepower: 200 @ 4000 RPM. Torque: 325 @ 3200 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.415″. Carburetor:  Rochester four-barrel 7044266. Not Available in California.

1975-1979

Though the 400 would soldier on in the Firebird and would continue to receive a 4 barrel, it was basically a pedestrian engine, though for the period, perky. In 1980, the 400 was quietly dropped.

1975-1979 Pontiac 400 CID Engine Specifications
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175 Horsepower  L65 400 CID V-8 – All Series, Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.0:1. Horsepower: 170 @ 3600 RPM. Torque: 320 @ 2000 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 55°, Lift (intake) 0.377″; (exhaust) 0.413″. Carburetor:  Rochester two-barrel 7044066; (Full Size Station Wagon) 70440670. (California) 7044067. Single Exhaust.

200 Horsepower L78  V-8 – All Series, Hydra-matic Transmission: Overhead valves. Cast iron block. Displacement: 400 CID. Bore and stroke: 4.125″ x 3.750″. Compression ratio: 8.0:1. Horsepower: 200 @ 4000 RPM. Torque: 325 @ 3200 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.415″. Carburetor:  Rochester four-barrel 7044266. Not Available in California.

350 CID V8 (1968-1976)

In 1968 the 326 was replaced by the 350, 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

This engine was offered in both 2bbl and 4bbl 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
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Tempest Base V-8 – All Transmissions: Cast Iron Block. Displacement: 350 CID. Bore and stroke: 3.8750″ x 3.75″ Compression ratio: 9.2:1. Horsepower: 265 @ 4600 RPM. Torque: 355 @ 2800 RPM. Five main bearings.  Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″. Carburetor: Rochester 2-barrel (manual transmission) 7028071 (automatic) 7028062.

Tempest Optional V-8 – All Transmissions: Cast Iron Block. Displacement: 350 CID. Bore and stroke: 3.875″ x 3.75″ Compression ratio: 10.75:1. Horsepower: 320 @ 5100 RPM. Torque: 359 @ 2900 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: (manual trans: Intake 273°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″; (automatic trans: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″. Carburetor: Rochester (manual transmission) 7028269, (automatic) 7028266.

1969

This engine was also offered in 1969 along with a second HO version. The later 350 HO was rated at 330 hp, and was equipped with the 400 CI large valve heads (# 48 with 2.11 intake and 1.77″ exhaust valves) and the 400 HO camshaft (068).

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

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

Tempest Optional V-8 – All Transmissions: Cast Iron Block. Displacement: 350 CID. Bore and stroke: 3.8750″ x 3.75″ Compression ratio: 10.75:1. Horsepower: 330 @ 5100 RPM. Torque: 380 @ 3200 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration:(manual trans: Intake 301°, Exhaust 313°, Overlap 76°, Lift (intake) 0.413″; (exhaust) 0.414″; (automatic trans: Intake 270°, Exhaust 289°, Overlap 54°, Lift (intake) 0.410″; (exhaust) 0.413″. Carburetor: Rochester (manual transmission) 7029263, (automatic) 7029268.

1970

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.

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

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

1971-1976

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. 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

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

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

Base V-8 – Manual Transmission: Cast Iron Block. 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; (dual exhaust) 175 @ 4400 RPM. Torque: 275 @ 2000 RPM. Five main bearings.  Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″. Carburetor: Carter 2-barrel 488062.

Tempest Base V-8 – Hydra-matic Transmission: Cast Iron Block. 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; (dual exhaust) 175 @ 4400 RPM. Torque: 275 @ 2000 RPM. Five main bearings.  Hydraulic valve lifters. Camshaft Duration: Intake 273°, Exhaust 282°, Overlap 55°, Lift (intake) 0.410″; (exhaust) 0.414″. Carburetor: Rochester 2-barrel 7042062.

Base V-8 – Manual Transmission: Cast Iron Block. 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; (dual exhaust) 175 @ 4400 RPM. Torque: 280 @ 2400 RPM. Five main bearings.  Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 277°, Overlap 47°, Lift (intake) 0.376″; (exhaust) 0.412″. Carburetor: Rochester 2-barrel (manual transmission) 7043071; (automatic transmission) 7043062, (automatic transmission California) 7043063.

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.

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
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