The Golden Rocket J2 Engine

1957-1958 J2 Golden Rocket

There's no doubt about it; you have to have a good imagination to see the 1957 Oldsmobile 88 as a NASCAR racer. With its 1950s American styling and tipping the scales at something approaching two tons, this Olds is  very different from today's aerodynamic,  workshop fabricated race machines. However, it was so effective  with its new engine as an oval track race car  that US stock car racing's controlling body quickly banned it from competition.

This NASCAR Oldsmobile  was no ordinary 88;  it was built for speed, courtesy of the new 371 CID J2 engine. The J2 engine was a further development of Oldsmobile's original high compression Rocket V8  that came to life in 1949 with a displacement of 303 and later 324 cubic inches. The original was a good motor, detailed elsewhere, but lacked the punch to move the big GM sedans on the street. The 371 J2 was a different story. During the early to mid 1950s, the single carbureted Rocket V8 was a regular winner in NASCAR, but by 1957 competition had caught up and surpassed Oldsmobile. It was time to  even the score.

The factory performance  race was in full swing, and the track was the place to prove who was king. Showroom sales depended on racetrack success; Chrysler had the 300, Chevrolet had its new 283 small block, and Ford was experimenting with supercharging on the 312. Oldsmobile's solution was to increase the Rocket's displacement to 371, raise the compression from 9.5:1 to 10:1, add three Rochester 2 barrel carburetors, and dual exhaust. The new engine was known as the J2 Golden Rocket and now packed enough horsepower and torque to do some real damage.

Under normal driving road conditions, the center choke equipped 280 cfm Rochester 2G two barrel carburetor fed the big V8. When the accelerator was floored,  two more Rochester 2Gs,  each flowing 290cfm, opened up, giving the engine the benefit of  860cfm.
The J2's extras bumped the 371's power from its normal 277 bhp up to an impressive 300 bhp and  415 ft/lbs of torque. These were very good numbers for 1957.

Oldsmobile now went in search a of driving heavyweight and came up with Lee Petty,  father of NASCAR legend Richard Petty and winner of the 1954 Grand National Championship.
Eager to showcase its new engine's power, Oldsmobile made a deal that took place prior to the AMA racing ban.  After initial preparation,  which included an engine blueprint, solid cam, and adjustable rocker arms to distinguish it from the factory stock version, the J2 hit the track. Petty took the J2 powered Olds down the beach in the 1957 Daytona speed week contest at 144.9 miles an hour. 

 Bill France took one look at the numbers and promptly banned the engine in that configuration. He was correct in citing that it was not a regular production engine when it was initially introduced. Olds quickly changed that by offering the J2 to the public, but by then the ban was in place and France's ruling would remain. That put Oldsmobile's participation in Petty's racing activities at a standstill.  Below, a photo of one of Lee's  Oldsmobiles in the Petty junkyard in Level Cross. (No, it isn't there any more, they closed it) Petty raced the 1957 models for 2 years, winning his second NASCAR title. Oldsmobile did not provide any cars or help in 1958.

More changes were to come. Due to the AMA racing ban and pressure from the public because of the mounting highway death toll, Oldsmobile pulled  the J2 from the option list after the 1958 model year. After that, if you wanted to go fast you had to order parts and get under the hood. The J2 Tri Power setup will NOT fit the 303, 324 or 394. Offenhauser made a 3 x 2 manifold for the 371, shown below.

Oldsmobile produced 49,187 hardtops in 1957, making it the second most popular 88 body variant. Approximately  2500 were fitted with J2 packages during the 1957 and 1958 model years. Countless others were made at home by enterprising mechanics who knew what parts to order from Oldsmobile dealers.

The 1957 and 1958 J2 Golden Rocket engines had three two barrel carburetors with  vacuum
operated progressive linkage. Only the center carburetor was mechanically connected to the throttle pedal, and it was the only one equipped with a choke. When the center carburetor was opened  60° or more, engine vacuum drawn from the windshield wiper pump would simultaneously open the front and rear carburetors. I suppose it still worked when it was raining. These carburetors did not open progressively; they were either open or closed. 

The J2 engine also had a thinner head gasket, raising compression to 10.0:1. It was advertised with very conservative gross power and torque ratings of 312 hp  @ 4600 rpm and 415 ft·lbs  @ 2800 rpm. Oldsmobile charged a mere $83 for the J2 option. A special competition J-2 package was available also, but it cost $385 and had enough internal modifications that it was recommended only for competition and off road use.

In practice, owners who did not regularly drive hard enough to engage the front and rear carburetors experienced problems with the linkage and carburetor throats becoming clogged, and some J2 equipped cars had the front and rear carburetors removed and blocked off. The package was expensive to produce, and Oldsmobile discontinued it after 1958. Typical times for the 3700 lb car in street trim ran 0-60 in just under 8 seconds with the quarter mile in the high 15 second range. Top end was around 120.

These were good running cars, although not in the same league as the 300. They were Oldsmobile's  first real foray into street performance, and it worked out well. The tradition would resurface from time to time, particularly with the Starfire, and culminating in the 442.


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