Corvette Unlimited: The 1957 Corvette SS

There is probably good reason to suggest that if the early years of the Corvette had not been as disastrous as they were, the heritage of America’s sports car might not be as fully developed as it is. Rushed to market in six months, the first year’s car suffered from quality issues, inadequate product features and hugely limited availability.

Pent-up demand for the Corvette was likely responsible for sales of 3640 cars in 1954, but reality kicked down the door the following year when a mere 700 units were sold. Some contend that it was Ford’s introduction of the Thunderbird two-seat convertible in 1954 that saved the Corvette, but the more likely explanation is that the T-Bird merely gave GM management enough time to develop and prove the car.

While the Corvette SS resembled the production car, it was jsut a fiberglass shell over a tube steel space frame. The magnesium-bodied version would weigh in at just 1,700 pounds.

One of the key people in that effort was Zora Arkus-Duntov, an engineer on the Corvette team since 1953 and a former road racer from Europe. The engineer had seen Harley Earl’s 1953 Corvette prototype at the 1953 Motorama and immediately applied for work with GM, asking to be assigned to the Corvette. Arkus-Duntov had previously run a family business making and selling cylinder heads for the Ford flathead engine that enabled it to develop more than 300 HP.

When Chevrolet chief engineer, Ed Cole, hired Arkus-Duntov in the fall of 1953, it was to work on an upcoming small block V8 engine. He was able to improve the final design of the cylinder heads and cam on the 265 CI small block V8 that became an option on the 1955 Corvette. The new motor’s 195 HP improved on that of the ‘Blue Flame’ inline six which had driven the Corvette from its beginning.

Win On Sunday, Sell On Monday

Instead of crediting the Thunderbird, most Chevy faithful of the day suggested that a 1955 memo from Arkus-Duntov to Ed Cole, in which he promised to make the Corvette a commercial success, was what saved the car from a short future. In 1953, the Corvette engineer had presented a paper at a Society of Automotive Engineers (SAE) conference, suggesting that successful sports cars were “endowed with a racing halo provided by a few specialized machines of the same make.” Doubtless, this same approach was used with Cole, who was now general manager of Chevrolet.

The driver's feet sat very close to the exhaust headers, but the fiberglass body insulated them. When replaced with magnesium panels, no insulation was provided, which led to significant driver comfort issues in all but the shortest driving sessions.

It was a busy year for Chevrolet, unofficially placing a Corvette with an experimental 307 cubic inch engine eighth overall at the 12 Hours of Sebring, getting a 283 CI V8 ready for production and finalizing the development of mechanical fuel injection.

A significant redesign of the Corvette appeared for 1956 and many of the public’s perceived drawbacks had been addressed. Performance remained a priority and an optional 225 horsepower version of the 265 V8, using a pair of Rochester 4-barrel carburetors, was made available. Arkus-Duntov took a preproduction car to Pikes Peak early in 1956 and set a stock car record.

Cole subsequently approved a production speed record attempt at Daytona Beach, for which Arkus-Duntov took a 1956 model with the optional engine and removed the windshield. At GM’s desert proving grounds, he felt that another 30 HP was needed to meet the goal, so working with Chevrolet engineers over the phone, he developed the legendary ‘Duntov cam’ that, in February of 1956, helped Chevrolet set a production class record in the flying mile at Daytona Beach of 150.583 MPH.

It was a busy year for Chevrolet, unofficially placing a Corvette with an experimental 307 cubic inch engine eighth overall at the 12 Hours of Sebring, getting a 283 CI V8 ready for production and finalizing the development of mechanical fuel injection for the 1957 production. The glory of Sebring, however, never quite faded, and late in 1956 Ed Cole spoke to Arkus-Duntov about installing the small block engine into a D-Type Jaguar that Bill Mitchell had acquired.

Corvette chief engineer, Zora Arkus-Duntov (right), shows off some internals of the Corvette SS during a session at Sebring.

No More Half-Measures

Arkus-Duntov argued that they should build a full-race version of the Corvette and put it in the 1957 Sebring race. This would be his “specialized machine of the same make,” to which he referred in the SAE paper. Cole approved the plan, and the car needed to be ready within six months. Two versions were built. One, called the “Mule” was the primary development platform and used a fiberglass body over a steel tube space frame. The second car was to be the actual race entrant and would replace the composite body panels with hand-formed magnesium ones.

The car would use the latest iteration of the small block V8, equipped with fuel injection and delivering 307 horsepower. The front suspension consisted of unequal length A-arms with coilover springs and shock absorbers. The back end was made up with a de Dion axle, Halibrand quick-change differential and inboard, aluminum-finned drum brakes. Even with its composite body, the Mule weighed in at just 1,850 pounds. The magnesium panels would reduce this by a further 150 pounds, but time was not on the team’s side.

Despite everyone’s best efforts, testing at Sebring would have to be done using the Mule. World Champion, Juan Miguel Fangio, had previously been contracted to drive the SS at Sebring, but was released when it was evident that the car would not be ready. He drove a Maserati to victory that year, but retained an interest in the SS.

This is what the Corvette SS did best. It was fast immediately out of the box, but having been developed on an impossibly short timeline, there were additional issues to sort out. It never got the chance.

Both Fangio and Sterling Moss stopped by the Chevrolet team to see the Mule and Fangio took the car out during a practice session. Even in the heavier test car, Fangio beat his previous year’s record in it and set one of the fastest laps of the day.

According to reports, Bill Mitchell bought the Corvette SS mule from GM for one dollar.

When the actual race car arrived, all “sorted” parts were transferred from the Mule to the second chassis to get it ready. To be driven by Piero Taruffi and John Fitch, it retired after 23 laps with “electrical gremlins, bad brakes, and finally, terminal rear end problems.” During those first laps, however, it dominated the field and recorded a top speed of 183 MPH.

None of the problems identified would hold back future development of the car into a world class competitor destined for greatness at the Le Mans 24-hour race. An earlier version of that very race, however, would act to kill all chances for the Corvette SS. The 1957 AMA ban on manufacturer-supported racing ended all development and racing activities by American auto manufacturers. This action resulted from a horrific accident two years prior at Le Mans, when a disastrous crash killed 83 spectators and injured another 120 people.

According to reports, Bill Mitchell bought the Corvette SS mule from GM for one dollar. The car was reskinned and, while it met little success as a racer, the overall styling impressed all that saw it. Renamed the “Sting Ray,” this mule from the past would become a stallion for the future.

About the author

Don Roy

Don's background includes 14 years in the OEM and Tier2 domestic auto industry, as well as three years as Technical Editor of a muscle car enthusiast print magazine. He is a mechanical engineer by trade and completed his first project car when he was 16 years old - after rebuilding the engine in his bedroom. His hobbies include photography, film making and building the odd robot from time to time.
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