The Chevrolet Corvette SS is a
sports racing car
Sports car racing is a form of motorsport road racing which utilises sports cars that have two seats and enclosed wheels. They may be purpose-built prototypes or grand tourers based on road-going models. Broadly speaking, sports car racing is o ...
built by
Chevrolet
Chevrolet ( ), colloquially referred to as Chevy and formally the Chevrolet Motor Division of General Motors Company, is an American automobile division of the American manufacturer General Motors (GM). Louis Chevrolet (1878–1941) and ous ...
in 1957. The car raced once at the 1957
12 Hours of Sebring
The 12 Hours of Sebring is an annual motorsport endurance race for sports cars held at Sebring International Raceway, on the site of the former Hendricks Army Airfield World War II air base in Sebring, Florida, US. The event is the second round ...
before Chevrolet withdrew from all racing activities in response to a ban that year by the
Automobile Manufacturers Association
The Automobile Manufacturers Association was a trade group of automobile manufacturers which operated under various names in the United States from 1911 to 1999.
A different group called the Automobile Manufacturers' Association was active in the ...
for all of its member companies, which included GM.
History
By the mid-1950s GM engineer and future Director of High Performance
Zora Arkus-Duntov
Zora Arkus-Duntov (December 25, 1909 – April 21, 1996) was a Belgian-born American engineer whose work on the Chevrolet Corvette earned him the nickname "Father of the Corvette." He is sometimes erroneously referred to as the inventor of the Co ...
was convinced that publicity from Corvette racing victories would increase sales of the car.
Duntov took a team of three Corvettes to
Daytona Daytona refers to the city of Daytona Beach, Florida, or things named after it.
Daytona may also refer to:
Locations
* Daytona Beach Shores, Florida
* South Daytona, Florida
* The Daytona Beach metropolitan area
* Halifax area, also known as Da ...
Speedweeks
Daytona Speedweeks presented by AdventHealth is a series of racing events that take place during January and February at Daytona International Speedway. Traditionally leading up to the Daytona 500, in 2021 it concluded with the Daytona road cour ...
in February 1956; two cars that were essentially stock and one modified car.
John Fitch won the Sports Car division in one of the stock Corvettes, and
Betty Skelton
Betty Skelton Frankman Erde (June 28, 1926 – August 31, 2011) was a land speed record holder and aerobatics pilot who set 17 aviation and automobile records. She was known as "The First Lady of Firsts", and helped create opportunities for women ...
took second place in the other, while Duntov won the Modified Sports Car division in the modified car.
Four Corvettes, all with the new SR package and one with additional modifications including an enlarged engine, appeared in the
1956 12 Hours of Sebring
Events
January
* January 1 – The Anglo-Egyptian Condominium ends in Sudan.
* January 8 – Operation Auca: Five U.S. evangelical Christian missionaries, Nate Saint, Roger Youderian, Ed McCully, Jim Elliot and Pete Fleming, are k ...
. Duntov declined to participate, so Fitch acted as Team Manager.
General Manager of Chevrolet
Ed Cole
Edward Nicholas Cole (September 17, 1909 – May 2, 1977) was an American automotive executive for General Motors.
Career
Cole was the son of a dairy farmer. In his youth, he designed, built, and sold homemade radio sets, and as a teenage ...
, watching the 1956 Sebring race, realized that only a Corvette built specifically for racing stood a chance of winning against the international competition.
Two other racing Corvettes called SR-2s were built, one car for Jerry Earl, son of
Harley Earl
Harley Jarvis Earl (November 22, 1893 – April 10, 1969) was an American automotive designer and business executive. He was the initial designated head of design at General Motors, later becoming vice president, the first top executive ever ...
, the head of GM's Art and Color Section, and a second car for
Bill Mitchell.
At the
New York Auto Show
The New York International Auto Show is an annual auto show that is held in Manhattan in late March or early April. It is held at the Jacob Javits Convention Center. It usually opens on or just before Easter weekend and closes on the first Su ...
in December 1956 Chevrolet debuted the 1957 Corvette Super Sport, a show car based on a production Corvette with the latest engine and some features first seen on the SR and SR-2 racing cars.
Harley Earl brought Jack Ensley's
Jaguar D-Type
The Jaguar D-Type is a sports racing car that was produced by Jaguar Cars Ltd. between 1954 and 1957. Designed specifically to win the Le Mans 24-hour race, it shared the straight-6 XK engine and many mechanical components with its C-Type ...
into GM's Research Studio.
He instructed the team to convert the car to left-hand drive, install a Chevrolet V8 engine, and restyle the car incorporating styling cues from the production Corvette. Work on the D-Type conversion started May 1956.
Engineers working on the conversion identified several problems with Earl's idea, leading to the conversion being abandoned, and the project moving in another direction.
Some suggest that the entire D-Type episode was a ruse by Earl to get Duntov committed to the project.
The redirected project received GM designation XP-64, with approval given in August 1956 to ready two cars to race at Sebring in six months time.
The ultimate goal was to race the car in the
24 Hours of Le Mans
The 24 Hours of Le Mans (french: link=no, 24 Heures du Mans) is an endurance-focused Sports car racing, sports car race held annually near the town of Le Mans, France. It is the world's oldest active Endurance racing (motorsport), endurance r ...
.
GM designer
Clare MacKichan
Clare M. "Mac" MacKichan (/mækˈkiː.kæn/, March 10, 1918 – February 10, 1996) was an automotive designer and executive with General Motors (GM). He is best known for designing or overseeing the design of several significant models for the Ch ...
headed up the team designing the bodywork.
Also on the design team were
Robert Cumberford
Robert Wayne Cumberford (born August 4, 1935) is a former automotive designer for General Motors, author and design critic – widely known as Automotive Design Editor and outspoken columnist for ''Automobile'' magazine.
Examples of ...
and
Anatole Lapine
Anatole Carl "Tony" Lapine (born 23 May 1930 in Riga, Latvia, died 29 April 2012 in Baden-Baden, Germany) was an automotive designer and racing driver. Lapine worked for General Motors (GM), Opel, and Porsche. During his time as chief designer at ...
.
Some references include Bob Cadaret in this group.
Although the Jaguar was gone, its shape influenced MacKichan's design.
Development of the car's chassis, drivetrain and running gear took place in Duntov's
skunkworks
Skunk Works is an official trademark for the Lockheed Martin Advanced Development Programs (formerly Lockheed Advanced Development Projects).
Skunkworks or Skunk works may also refer to:
* ''Skunkworks'' (album), alternative rock album by Bruce ...
shop at GM.
At Lapine's suggestion, a
Mercedes-Benz 300 SL
The Mercedes-Benz 300 SL (chassis code W 198) is a two-seat sports car which was produced by Mercedes-Benz as a gullwinged coupe (1954–1957) and roadster (1957–1963).Werner Oswald: ''Mercedes-Benz Personenwagen 1945–1985''. Motorbuch Ve ...
was obtained, put up on stands and the body removed.
The Mercedes' chassis was cut and modified to accept a new small-block V8 drivetrain and new rear suspension of Duntov's design.
This first chassis was used to create a development mule that would receive a fiberglass body. That frame was also used as a template for building all subsequent SS chassis.
The official name for Project XP-64 was the Corvette SS. This was the first Chevrolet to wear the "SS" badge.
When Cole announced the car, it was described as an engineering project researching various features to improve both performance and safety.
The Corvette SS was Chevrolet's first purpose-built race car.
It was considered the successor to the three "SR" cars that raced at 1956 in Sebring, and the two SR-2 Corvettes,
which were based on a production Corvette chassis.
Two cars were completed; the development car called the "mule", and a full-spec Corvette SS. Three additional Corvette SS chassis were built, but not turned into complete cars.
Some references report that Mitchell later bought the complete development mule for just US$1 as the base for his Stingray racer.
In interviews Shinoda and Mitchell both describe Mitchell buying a spare SS chassis for US$500.
He estimated the value of the chassis at US$500,000.
After its career ended, the Corvette SS remained in storage at various locations within GM until Duntov convinced
John DeLorean
John Zachary DeLorean (January 6, 1925 – March 19, 2005) was an American engineer, inventor, and executive in the U.S. automobile industry, widely known for his work at General Motors and as founder of the DeLorean Motor Company.
DeLorean mana ...
, Chevrolet's new general manager, to donate the car to the
Indianapolis Motor Speedway
The Indianapolis Motor Speedway is an automobile racing circuit located in Speedway, Indiana, an enclave suburb of Indianapolis, Indiana. It is the home of the Indianapolis 500 and the Verizon 200, and and formerly the home of the United State ...
.
In 2006 a plan was made to apply the Corvette SS name to a special version of the
C6 Corvette.
This enhanced Corvette was eventually released as the Corvette ZR1.
Features
The chassis for the Corvette SS was a tubular steel space-frame unit inspired by that of the Mercedes-Benz 300 SL.
The full-spec car had a body made of magnesium, rather than the fiberglass used by production Corvettes.
The mule had a fiberglass body. A transparent bubble top was also produced for the car, but was not used when racing.
Front suspension was by short-long arms with coil springs over tubular shock absorbers. At the rear was a
De Dion tube
De Dion rear axle
A de Dion tube is a form of non-independent automobile suspension. It is a considerable improvement over the swing axle, Hotchkiss drive, or live axle. Because it plays no part in transmitting power to the drive wheels, it is ...
with two pairs of trailing arms and coil over shocks.
The engine in the Corvette SS was a production
Chevrolet small block V8 that displaced .
It was fitted with
Rochester Ramjet fuel injection. 9.0:1 compression aluminum cylinder heads and a deep-sump oil pan made of magnesium were used.
The camshaft was a special “Duntov” profile solid-lifter piece. The exhaust system used the tuned-length headers developed for the SR2.
Power output was and .
The transmission was a close ratio four-speed
Borg Warner
BorgWarner Inc. is an American automotive supplier headquartered in Auburn Hills, Michigan. The company maintains production facilities and technical systems at 93 sites (as of June 6, 2022) in 22 countries worldwide and has around 49,000 employ ...
manual
Manual may refer to:
Instructions
* User guide
* Owner's manual
* Instruction manual (gaming)
* Online help
Other uses
* Manual (music), a keyboard, as for an organ
* Manual (band)
* Manual transmission
* Manual, a bicycle technique similar to ...
with an aluminum alloy case.
The differential was a Halibrand quick-change unit. Depending on the gearset installed, top speed was between .
The brakes were twin-leading-shoe Center-Plane mechanisms from Chrysler with a custom GM designed Al-Fin drum made up of an iron face and inner surface and finned aluminum cover. Heat transfer was increased by flowing aluminum through over 100 holes drilled in the iron drum.
The brakes were inboard at the rear.
Overall weight for the complete car was .
Technical data
Motorsports
Duntov had originally signed
Juan Manuel Fangio
Juan Manuel Fangio (American Spanish: , ; 24 June 1911 – 17 July 1995), nicknamed ''El Chueco'' ("the bowlegged" or "bandy legged one") or ''El Maestro'' ("The Master" or "The Teacher"), was an Argentine racing car driver. He dominated t ...
and
Carroll Shelby
Carroll Hall Shelby (January 11, 1923 – May 10, 2012) was an American automotive designer, racing driver, and entrepreneur. Shelby is best known for his involvement with the AC Cobra and Mustang for Ford Motor Company, which he modified duri ...
to drive the car at Sebring in 1957, but both asked to be released from their contracts, so Fitch and
Piero Taruffi
Piero Taruffi (12 October 1906 – 12 January 1988) was a racing driver from Italy.
Sports car career
Taruffi began his motorsport career racing motorcycles. He won the 1932 500cc European Championship on a Norton and in 1937 set the motorcycle ...
were substituted on short notice.
In practice, and driving the mule rather than the full-spec SS, Fitch managed a lap time of 3:32, while Taruffi turned in a time of 3:35 in the same car. Duntov persuaded both
Stirling Moss
Sir Stirling Craufurd Moss (17 September 1929 – 12 April 2020) was a British Formula One racing driver. An inductee into the International Motorsports Hall of Fame, he won 212 of the 529 races he entered across several categories of comp ...
and Fangio to try the mule in practice, and they turned in times of 3:28.2 and 3:27.2 respectively.
Late Friday Fitch did a few laps in the magnesium-bodied SS, and found that while the fiberglass body of the mule insulated the driver from heat produced by the engine, the magnesium body provided no such protection, allowing the heat into the interior unimpeded. He also encountered problems with the brakes on the car. Parts from the mule were swapped over to the SS.
For the race, the starting grid was determined by engine displacement, so the SS started in the number one position. Fitch was in the car for the Le Mans start. After the third lap he pitted to have two front tires replaced, then turned in a lap time of 3:29.8; the fastest lap the SS would achieve. Fitch later pitted to have first a coil wire, then the coil itself, replaced. The car began to overheat. Then the bushings tying the rear lower trailing arms to the chassis split due to having been installed improperly. Fitch retired the SS after 23 laps.
In April 1957, the
Automobile Manufacturers Association
The Automobile Manufacturers Association was a trade group of automobile manufacturers which operated under various names in the United States from 1911 to 1999.
A different group called the Automobile Manufacturers' Association was active in the ...
(AMA) voted to enact a ban on motor racing for all of its member companies, which included GM. The ban went into effect on 1 June, and GM accordingly withdrew the SS from further racing.
The drivers that had been arranged for the 1957 Le Mans did not learn of the withdrawal until a month and a half after Sebring."
For 1958 the
Fédération Internationale de l'Automobile
The Fédération Internationale de l'Automobile (FIA; en, International Automobile Federation) is an association established on 20 June 1904 to represent the interests of motoring organisations and motor car users. It is the governing body for ...
(FIA) reduced the maximum displacement limit to 3.0 liters for sports cars, effectively disqualifying the Corvette SS from any future European events.
At the opening of the Daytona Motor Speedway in 1959, Duntov took the SS out on the track and set fastest lap with a speed of .
Further reading
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References
{{Corvette timeline
Chevrolet Corvette
Rear-wheel-drive vehicles
Sports racing cars
Roadsters
Cars introduced in 1957