1953-1960 Cadillac V-8 Facts
The 1950s Cadillac V-8 started out featuring smooth quiet and reliable power due to its new overhead valve high compression V-8, but the factory soon found that its competitors were touting power! Not to be outdone, the 1955 Eldorado appeared with multiple carbs and the horsepower race was on!
The Growth of the Cadillac V-8 in size and power from 1953 through 1960
Introduction
For 1949, General Motors jumped the entire US auto market by releasing the Cadillac and Oldsmobile V-8. Both engines were overhead valve designs released in cars like Buick and Nash but with an important difference – the high compression “wedge” combustion chamber. This configuration was the result of extensive testing by William Kettering and his staff post WW II.
The 331 CID V-8
The Cadillac 331 engine featured an open runner intake manifold that required the use of a tappet valve cover, a rear-mounted distributor, and shaft-mounted rocker arms. The crankshaft end play was carried by the rear main bearing. Significant was the use of a lighter “skirt less” block where it ended at the centerline of the crankshaft. Thus, the oil pan attachment flange does not descend much below the crankshaft centerline. Another feature was that the rear of the block only extended back as a only a partial clutch housing. In 1955 the Cadillac engine went to a lighter “flat back” block that bolted to a now common clutch and flywheel housing set between the engine and transmission.
Bore and stroke were 3.8125″ x 3.625″ for an overall displacement of 331.1 CID. The engine featured an oiling system that used a central cast-in passage between the lifter galleries feeding oil to the cam and crankshaft by grooves machined into the cam bores. A single drilled passage per bearing saddle feeds both cam and crank journals. The hydraulic lifters were oiled through small oil feeds instead of having the lifter bore intersect the right and left side oil supply galleries.
Since Cadillac s used a hydraulic camshaft, there was no provision for adjustment on the rocker arms. An interesting note is that the Studebaker OHV V-8 was similar enough that many early racers would replace the Cadillac rocker assemblies with adjustable rockers (and sometime even the lifters themselves) from the Studebaker V8 for operation at higher engine speeds.
Aside from increases in compression, and the addition of a 4-barrel carburetor in 1953, the engine remained unchanged until 1955. In 1955 the Eldorado (optional on other Cadillacs) received a dual 4-barrel intake manifold increasing the standard model’s 250 HP to 270.
The 365 CID V-8
Displacement was increased to 365 CID for 1956 by increasing the bore to 4.00″ and keeping the stroke at 3.625″. The base version would use a single 4 barrel carburetor from 1956 through 1958. The 1956 base engine produced 285 horsepower, while the Eldorado made 305, utilizing twin 4-barrels. Camshaft duration increased as well. The 1957 base version raised the engine output to 300 horsepower, while the Eldorado made 325. In 1958 the base version’s power went to 310 and the Eldorado, now utilizing a 3 2-barrel manifold,produced 335 HP. The Eldorado engines were optional on all other Cadillacs, except in 1957, though it could be dealer installed.
The 390 CID V-8
A longer, 3.875″ stroke pushed displacement to 390 CID for 1959, moving the base engine’s power up to 325. The Eldorado tri-power reached 345 horsepower. Surprisingly, the engine was unchanged for 1960 and the Eldorado optional engine was no longer featured after this year.
Please see each tab section for a breakdown of the available variants of the engine over time.
1953 331 CID V-8
The 331 was in its second year of 4-barrel carburetion. Compression ration was up from 7.5:1 to 8.25:1, resulting in a horsepower jump from 190 to 210 and a torque increase from 322 to 330.
1953 Cadillac 331 CID Engine Specifications
Click the tabs for specific engine information
Cadillac V-8: Overhead valves. Cast Iron Block. Displacement: 331 CID. Bore and stroke: 3.8125″ x 3.625″. Horsepower: 210 @ 4150 RPM. Torque: 330 ft. lbs. @ 2700 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 270°, Overlap 49°, Lift (Intake) 0.365″ (Exhaust) 0.365″. Compression ratio: 8.25:1. Carburetors: Carter WCFB 2005S or Rochester 4CG 7006963 with AC, 7006962 without AC.
1954 331 CID V-8
In its next to last year at the 331 CID level, the engine now produced 230 horsepower and 330 ft. lbs, of torque. Compression did not increase from 8.25:1.
1954 Cadillac 331 CID Engine Specifications
Click the tabs for specific engine information
Cadillac V-8: Overhead valves. Cast Iron Block. Displacement: 331 CID. Bore and stroke: 3.8125″ x 3.625″. Horsepower: 230 @ 4400 RPM. Torque: 330 ft. lbs. @ 2700 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 270°, Overlap 49°, Lift (Intake) 0.365″ (Exhaust) 0.365″. Compression ratio: 8.25:1. Carburetor: Carter WCFB four-barrel Models 2109S also 2143S, and 2110S. Also fitted: Rochester 4GC four-barrel (with Air Conditioning) Model 7006963; (without Air Conditioning) Model 7006962
1955 331 CID V-8
This would be the last year at the 331 CID level, the engine now produced 250 horsepower and 345 ft. lbs, of torque. Compression increased from 8.25:1 to 9.0:1. Important was that a new engine was offered on the Eldorado with 270 horsepower.
1955 Cadillac 331 CID Engine Specifications
Click the tabs for specific engine information
Cadillac V-8. Overhead valves. Cast Iron Block. Displacement: 331 CID. Bore and stroke: 3.8125″ x 3.625″. Compression ratio: 9.0:1. Horsepower: 250 @ 4600 RPM. Torque: 345 @ 2800 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 270°, Overlap 49°, Lift (Intake) 0.365″ (Exhaust) 0.365″. Carburetor: Carter WCFB four-barrel. Models 2185S, or 2266S; with air conditioning 2186S or 2267S. Also Rochester 4GC four-barrel, Without air conditioning Model 7007970, With air conditioning Model 7007971
Eldorado V-8. Overhead valve. Cast Iron Block. Displacement: 331 CID. Bore and stroke: 3.8125″ x 3.625″. Compression ratio: 9.0:1. Horsepower: 270 @ 4800 RPM. Torque: 345 @ 3200 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 269°, Exhaust 270°, Overlap 49°, Lift (Intake) 0.365″ (Exhaust) 0.365″. Carburetors: Two (2) Rochester 4GC four-barrels; Front Model 7007240; Rear, without air conditioning Model 7007241; Rear, with air conditioning Model 7007242.
1956 365 CID V-8
A larger engine appeared this year, with the block displacement increased to 365 CID via a bore increase to 4.00″ and retaining the 3.625″ stroke. Horsepower jumped appreciably – now at 285 for the base engine and 305 for the Eldorado.
1956 Cadillac 365 CID Engine Specifications
Click the tabs for specific engine information
Cadillac V-8. Overhead valves. Cast Iron Block. Displacement: 365 CID. Bore and stroke: 4.00″ x 3.625″. Compression ratio: 9.75:1. Horsepower: 285 @ 4600 RPM. Torque: 400 @ 2800 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°), Overlap 102° (52°), Lift (Intake) 0.451″ (Exhaust) 0.451″. Carburetor: Carter WCFB four-barrel. Models 2333S, with air conditioning 2434S. Also Rochester 4GC four-barrel, Without air conditioning Model 7008750, With air conditioning Model 7008751.
NOTE: Beginning this year, regarding camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.
Eldorado V-8. Overhead valves. Cast Iron Block. Displacement: 365 CID. Bore and stroke: 4.00″ x 3.625″. Compression ratio: 9.75:1. Horsepower: 305 @ 4700 RPM. Torque: 400 @ 2800 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°), Overlap 102° (52°), Lift (Intake) 0.451″ (Exhaust) 0.451″. Carburetor: Two Carter WCFB four-barrels, (front) model 2371S, (rear) model 2372S (rear) with air conditioning 2373S. Also two Rochester 4GC four-barrels, (front) model 7008752, (rear) model 7008753 (rear) with air conditioning Model 7008754.
NOTE: Beginning this year, regarding camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.
1957 365 CID V-8
The horsepower was up on the 365 CID V-8, due to an increase in compression from 9.75:1 to 10.00:1. and an increase in intake valve head size from 1.750″ to 1.875″.
1957 Cadillac 365 CID Engine Specifications
Click the tabs for specific engine information
Cadillac V-8. Overhead valves. Cast Iron Block. Displacement: 365 CID. Bore and stroke: 4.00″ x 3.625″. Compression ratio: 10.0:1. Horsepower: 300 @ 4800 RPM. Torque: 400 @ 2800 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°), Overlap 102° (52°), Lift (Intake) 0.451″ (Exhaust) 0.451″. Carburetor: Carter WCFB four-barrel. Models 24795, with air conditioning 24808. Also Rochester 4GC four-barrel, Without air conditioning Model 7010100, With air conditioning Model 7010101.
NOTE: Regarding advertised camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.
Eldorado V-8. Overhead valves. Cast Iron Block. Displacement: 365 CID. Bore and stroke: 4.00″ x 3.625″. Compression ratio: 10.0:1. Horsepower: 325 @ 4800 RPM. Torque: 400 @ 3300 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°), Overlap 102° (52°), Lift (Intake) 0.451″ (Exhaust) 0.451″. Carburetor: Two Carter WCFB four-barrels, (front) model 25825, (rear) model 25835 (rear). Also two Rochester 4GC four-barrels, (front) model 7010302, (rear) model 7010300.
NOTE: This engine – Q Code, was only available in the Eldorado line this year, though the intake could be dealer installed.
NOTE: Regarding advertised camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.
1958 365 CID V-8
The horsepower was up on the 365 CID V-8, due to an increase in compression from 10.00:1 to 10.25:1. The Eldorado engine changed over from twin 4-barrel carburetors to three 2-barrel units – ostensibly for smoother “tip in” at wide open throttle.
1958 Cadillac 365 CID Engine Specifications
Click the tabs for specific engine information
Cadillac V-8: Overhead valves. Cast Iron Block. Displacement: 365 CID. Bore and stroke: 4.00″ x 3.625″. Compression ratio: 10.25:1. Horsepower: 310 @ 4800 RPM. Torque: 405 @ 3100 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°), Overlap 98° (48°), Lift (Intake) 0.451″ (Exhaust) 0.451″. Rochester 4GC four-barrel, Without air conditioning Model 7012010, With air conditioning Model 7012011.
NOTE: Regarding advertised camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.
Eldorado V-8: Overhead valves. Cast Iron Block. Displacement: 365 CID. Bore and stroke: 4.00″ x 3.625″. Compression ratio: 10.25:1. Horsepower: 335 @ 4800 RPM. Torque: 405 @ 3400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°), Overlap 102° (48°), Lift (Intake) 0.451″ (Exhaust) 0.451″. Carburetor: Three Rochester 2GC two-barrels, (front) model 7012201, (center) 7012202, (center w/air conditioning 7012205 (rear) model 7012203.
NOTE: This engine was available in all lines as an option – except Series 75 .
NOTE: Regarding advertised camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.
1959 390 CID V-8
The engine received another displacement boost this year, with the stroke growing to 3.875″ for 390 CID. Horsepower was also up due to this displacement increase and the compression ratio growing to 10.5.:1. The Eldorado engine reached its highest horsepower to date at 345, while the standard engine was now pushing 325..
1959 Cadillac 390 CID Engine Specifications
Click the tabs for specific engine information
Cadillac V-8: Overhead valves. Cast Iron Block. Displacement: 390 CID. Bore and stroke: 4.00″ x 3.875″. Compression ratio: 10.5:1. Horsepower: 325 @ 4800 RPM. Torque: 430 @ 3100 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°) Overlap 98° (48°). 0.451″ (Exhaust) 0.451″. Carburetor: Rochester 4GC four-barrel Model 7013030, or Carter AFB 2814S, #1471814 with air conditioning #1471815.
NOTE: Regarding advertised camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.
Eldorado V-8: Overhead valves. Cast Iron Block. Displacement: 390 CID. Bore and stroke: 4.00″ x 3.875″. Compression ratio: 10.5:1. Horsepower: 345 @ 4800 RPM. Torque: 405 @ 3400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°), Overlap 98° (48°), Lift (Intake) 0.451″ (Exhaust) 0.451″. Carburetor: Three Rochester 2GC two-barrels, (front) model 7013033, (center) 7013034, (center w/air conditioning 7013037 (rear) model 7013035.
NOTE: This engine was available as an option in all lines except Series 75.
NOTE: Regarding advertised camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.
1960 390 CID V-8
Cadillac stood pat this year, with no changes in engine size or horsepower. The Eldorado engine at 345, as did the standard engine at 325. Alas, this would be the last year of the special Eldorado engine.
1960 Cadillac 390 CID Engine Specifications
Click the tabs for specific engine information
Cadillac V-8: Overhead valves. Cast Iron Block. Displacement: 390 CID. Bore and stroke: 4.00″ x 3.875″. Compression ratio: 10.5:1. Horsepower: 325 @ 4800 RPM. Torque: 430 @ 3100 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°) Overlap 98° (48°). 0.451″ (Exhaust) 0.451″. Carburetor: Rochester 4GC four-barrel Model 7013030, or Carter AFB 2814S, #1471814 with air conditioning #1471815.
NOTE: Regarding advertised camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.
Eldorado V-8: Overhead valves. Cast Iron Block. Displacement: 390 CID. Bore and stroke: 4.00″ x 3.875″. Compression ratio: 10.5:1. Horsepower: 345 @ 4800 RPM. Torque: 405 @ 3400 RPM. Five main bearings. Hydraulic valve lifters. Camshaft Duration: Intake 324° (274°), Exhaust 324° (274°), Overlap 98° (48°), Lift (Intake) 0.451″ (Exhaust) 0.451″. Carburetor: Three Rochester 2GC two-barrels, (front) model 7013033, (center) 7013034, (center w/air conditioning 7013037 (rear) model 7013035.
NOTE: This engine was available as an option in all lines except Series 75.
NOTE: Regarding advertised camshaft duration, Cadillac counted the hydraulic lifter “ramp” which allowed the lifter to fill with fluid, but did not appreciably lift the valve. The more accurate duration was at about 50 degrees of camshaft rotation – hence the true duration is shown in parenthesis.