Bow Tie Breakthroughs: Chevrolet’s Quest For One HP-Per-Cubic Inch

This is the story of how a mysterious company called Raceway Enterprises helped Chevrolet attain the specific horsepower goal of one horsepower-per-cubic-inch of displacement in 1956, and along the way, they saved the Corvette from becoming just a curious footnote in the history of Detroit automotive manufacturing.

Long before that occurred, a young man that had aspired to be a lawyer, ended up working part-time in an auto parts store in Grand Rapids, Michigan. He was attending community college, and while there,  changed his mind and enrolled in the General Motors Institute instead. At the university in Flint, Michigan, his superior academic and leadership talents became well known, and he was offered a job with General Motors before he even graduated.

Initially working in the engineering department at Cadillac, Ed Cole rose to co-head a team that developed the Cadillac 331 cubic-inch overhead valve V8 engine. Among the distinctive features designed into that engine were a skirtless engine block, rear-mounted distributor, shaft-mounted rocker arms, and a novel oiling system that would be used both by Chevrolet and Ford well into the future. With a 7.5:1 compression ratio, the 331 cubic-inch engine delivered 160 horsepower at 3,800 rpm, but torque was massive, at 312 ft-lb at 1,800 rpm.

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In May of 1952, Cole became chief engineer at the Chevrolet Division, and his top priority was to introduce a low cost, light-weight V8 engine into the Chevrolet lineup. The project rapidly became a priority, in part, to try and reverse the flagging fortunes of the recently-introduced Corvette sports car.

The all-new 265 cid V8 engine from Chevrolet debuted in 1955. Wildly successful, more than 40-percent of Chevrolet cars that year were built with it. Image courtesy Corvette Story

Later interviewed about the engine and its development process, Cole explained, “I had worked on V8 engines all my professional life. I had lived and breathed engines. (Harry) Barr and I were always saying how we would do it if we ever design a new engine. You just know you want five main bearings – there’s no decision to make. We knew that a certain bore/stroke relationship was the most compact. We knew we’d like a displacement of 265 cubic-inches, and that automatically established the bore and stroke. And we never changed any of this. We released our engine for tooling direct from the drawing boards – that’s how crazy and confident we were.”

Special recognition was afforded those cars equipped with the new 265cid engine. A gold ‘V’ was included in the Chevrolet logo. Image courtesy Corvette Story

Cole had reason for his confidence, despite Chevrolet’s past history with V8 engines. This was the division’s first since 1917, and it was an immediate success. Well over 40-percent of Chevrolet’s 1955 production would carry the GM small-block engine. As successful as 1955 was for Chevrolet, it was a disaster for the Corvette team. Production had been moved to St. Louis, to a new assembly plant designed to build ten thousand sports cars yearly.

A Corvette engineer, Zora Arkus-Duntov, had been pushing to replace the “Blue Flame” inline six-cylinder engine with a more powerful one. His wish came true for the 1955 model year with the 195 horsepower small-block eight, but a manual transmission would not become available until the end of the production run. It wasn’t enough to convince a public that had become skeptical about the ‘Vette’s pretensions of being a sports car.

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In 1953, just three hundred Corvettes were built, and these were mostly sold to GM insiders and public opinion “influencers,” which was a major disappointment to the many who had enthused wildly over Harley Earl’s concept car at the 1953 Motorama. Ordinary members of the public would have to wait for the 1954 model to place an order.

The first year of Corvette production – 300 in all – were mostly sold to GM executives and high public figures, such as politicians and actors.

Even then, the Corvette lacked many features – manual transmission and wind-up windows, for example – that were commonplace on competing cars from Europe. While the pent-up demand led to sales of 3,640 units, it could not be sustained in 1955. Cars sat unsold on dealership lots for months at at time, and when the year-end total was calculated, it came to a meager seven hundred cars. According to some, it was Ford’s introduction of the two-seat Thunderbird in 1954 that kept the Corvette, from becoming nothing more than a short experiment in advanced plastics manufacturing.

A major redesign of the Corvette had been in the works, and in 1956, many of the public’s perceived drawbacks had been addressed. Performance remained a priority, so an optional 225 horsepower version of the 265 cubic-inch V8, used a pair of Rochester four-barrel carburetors, was made available. An optional 3.27 rear axle ratio could also be ordered. In his spare time, Duntov had developed a ‘high lift’ camshaft for the 265 that, with the dual four-barrel carburetors, boosted output to 240 horsepower.

By mid-year, Ed Cole had been promoted to General Manager of Chevrolet. Cole, and others, felt that the Corvette could be made a viable sports car by showing that it could successfully be raced in production car classes. Early in 1956, Duntov took a preproduction car to Pikes Peak and set a stock car record, using the 265 cubic-inch V8. Cole later sent him to Daytona Beach, where he established a new record of 150 mph on the flying mile, driving a modified, 307 cubic-inch-powered Corvette.

Based on that success, Cole announced that the Chevrolet Division would provide factory support to a private team entering Corvettes at the 1956 Sebring 12-hour endurance race. The sixth annual race was the first time that four major European car companies – Ferrari, Jaguar, Aston Martin, and Maserati – officially entered factory teams. A previously unknown company, Raceway Enterprises of Dundee, Illinois, entered four 1956 Corvettes in the race.

Four Corvettes were present for the 1956 Sebring 12-hour endurance race. They were entered by ‘Raceway Enterprises’ – a company not heard of prior or since.

The 24th of March, 1956, saw warm and dry weather over Sebring, Florida, for Round 2 of the World Sports Car Championship. Spectators at the 5.2-mile circuit would see 194 laps completed by Juan Miguel Fangio and his factory Ferrari 860 Monza during the 12-hour race. Carroll Shelby, with two other drivers, finished fourth, driving an Aston Martin DB3S.

The sole entrant in the Sports 8000 class was the Raceway Enterprises number 1 Corvette driven by John Fitch and Walt Hansgen and finished in ninth place overall. The car was fitted with a 307 cubic-inch engine, while the remaining Corvettes were running the 265 V8. The Raceway Enterprises Number 6 Corvette had been fitted with a 3.70 rear axle ratio and finished the race in 15th place overall.

Corvette sales rebounded in 1956, and many feel that racing victories made a significant contribution to the 3,467 units sold. Duntov and Cole had continued to further their goals of significantly improving the performance story, and had been working with GM’s Rochester Carburetor Division. Sebring losses in prior years had aptly demonstrated that fuel injection systems, as run in Mercedes competition cars, had a significant advantage.

Plans to increase the displacement of the small-block engine were in place as well. The 265 cubic-inch V8 used an over-square 3.75-inch bore and 3-inch stroke. For the 1957 model year, the block was bored out  to 3.875-inches, which resulted in a total displacement of 283 cubic-inches. The stock engine delivered 210 horsepower with a single four-barrel carburetor, but could be ordered with dual quads in either 245 or 270 horsepower configurations.

Option 579B configured the Corvette’s new 283 engine with Rochester mechanical fuel injection, giving it 283 horsepower and squarely hitting the 1 horsepower per cubic-inch milestone.

For the first time ever, mechanical fuel injection became an option (Code 579B among others) and, when fitted to the 283 engine, it would produce 283 horsepower. This is considered the first time in history that a production GM engine hit the one-horsepower-per-cubic-inch of displacement level. It was still an expensive option, adding more than ten percent to the car’s cost, but about 750 cars were built in this configuration. Another 284 fuel injected Corvettes were built that year, but with slightly lower power output.

579B-optioned Corvettes are widely sought after for their historical relevance. This fuel-injected example sold for $90,000 at the Mecum St. Charles, Auction in September, 2010.

By today’s standards, the Rochester design was primitive. A full description of the system is beyond our scope here, but as a mechanically-based multiport system, it managed fuel delivery and bypass according to vacuum signals, forsaking a timed injection approach for simplicity and a degree of increased reliability in competition use.

Between the new-found power levels and an optional four-speed manual transmission, Corvettes sales blossomed to 6,339 units that year, and set the stage for its continued production through present day, supported along the way by racing activities supported both by Chevrolet and many privateers. The darkest days were over for America’s sports car, and still, the best days were yet to come.

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