Rare drawings, documents reveal secret history of mid engine Corvette
From an acclaimed concept car John DeLorean reportedly dismissed because he wanted something “smaller and more European,” to the design that ended a feud between a pair of GM giants — but may have set the Corvette back decades — a trove of unique documents, sketches and models tells a secret history of the 60-year quest to build a mid engine Chevrolet Corvette.
The story begins in the late 1950s with legendary Corvette chief engineer Zora Arkus-Duntov and came to fruition when the first mid engine 2020 Corvette Stingray sold for $3 million at auction in January.
Titled “The Vision Realized: 60 Years of Mid engine Corvette Design” and created by GM Design Archive & Collections, the exhibit included 19 original sketches by designers including Larry Shinoda and Tom Peters, the massive 4-Rotor rotary engine from the 1973 Aerovette engineering, a wood wind-tunnel model, even letters from Arkus-Duntov’s personal files.
“The story of the mid engine Corvette is incredibly complicated, full of fits and starts,” said Christo Datini, manager of the GM Design Archive & Collections.
Cristo Datini at the General Motors Warren Technical Center in Warren, Michigan on Friday, January, 31, 2020 (Photo: Eric Seals, Detroit Free Press)
A mid engine Corvette was a dream shared by GM designers and engineers. The layout, in which the engine is behind the passenger compartment and immediately over the rear wheels, improves acceleration and handling. It’s been a mainstay at Ferrari for decades, and inspired repeated design and engineering projects at GM. None of them made it to production till now, largely because the Corvette’s original front-engine layout was so successful.
“Why would we change the Corvette?” GM chairman and CEO Richard Gerstenberg said to Arkus-Duntov before both men retired in the mid-1970s. “We sell every one we can make.”
‘Design without limit’
A generation of GM designers and engineers had already fought that attitude toward the sports car that debuted in 1953 model, and a couple more would before the midengine eighth-generation C8 Corvette Stingray debuted last year.
The exhibition included dozens of sketches, models, photos and documents.
“Our mission is to preserve the heritage of GM Design and educate our designers on GM’s prominence in the world of design,” Datini said. The archive also is working with the Detroit Institute of Arts on a massive exhibition dedicated to automotive design that opens this summer.
The Corvette exhibition closed at the end of January, but elements of it are likely to be displayed at other events and locations, possibly including the National Corvette Museum in Bowling Green, Kentucky, which provided materials for the collection.
Original magazines with drawings of what Corvettes could have looked like on display at the General Motors Warren Technical Center in Warren, Michigan on Friday, January, 31, 2020 (Photo: Eric Seals, Detroit Free Press)
Chevrolet Engineering Research Vehicle I, Also called SERV I and XP-708, was the beginning. A running model that debuted in 1960, the car had the looks of an Indy car and a chassis that tested what a midengine layout could do. It was “a design without limit” and an “admirable tool” to help Chevy figure out “what to put in Corvette,” said Duntov, himself a former driver in the 24 Hours of Le Mans sports car race.
CERV I was used as a test vehicle for years. Larry Shinoda, who would go on to be known as the father of the ’63 Corvette Stingray and the Mako Shark concept car, tweaked its design repeatedly as engineers tested it with seven different power trains.
GM eventually retired CERV I, selling it to the Briggs Cunningham Automotive Museum for $1. When the museum failed in the 1980s, GM bought it back for “somewhat more,” Datini said.
A model of the 1968 Chevrolet mid-engine Corvette Roadster that is one of many items for General Motors workers to see at the Corvette design display at the General Motors Warren Technical Center in Warren, Michigan on Friday, January, 31, 2020 (Photo: Eric Seals, Detroit Free Press)
Corvettes the world never saw
Shortly thereafter, Duntov heard rumors Ford was developing a Le Mans racer to challenge Ferrari and launched work on CERV II. GM decided not to race, Ford and Carroll Shelby built the GT40 that inspired “Ford vs. Ferrari,” and the CERV II was used as an engineering test bed at secret proving grounds and never seen by the public during its active lifetime. Built in 1964, CERV II had a 500-horsepower V8, 210-mph top speed and 2.8-second 0-60 mph time.
A picture of the CERV II Corvette. The sports car never went into production but it was influential in the design of the C5 production Corvette. (Photo: Eric Seals, Detroit Free Press)
“By that time, engineers and designers knew a midengine chassis was necessary” to get maximum performance from the ‘Vette, Datini said. Putting the engine behind the passenger compartment puts the car’s weight over the rear wheels to put down more power without spinning. Shifting balance from the production ‘Vette’s nose-heavy weight distribution would also improve handling.
Also in 1964, the XP-819 experimental car was being tested. Designed by Shinoda, it bore a strong resemblance to 1970 Corvettes, but Duntov hated it, calling it an “ugly duckling” at least in part because he wished his engineering team got some of the budget allotted to designing the car. It had a 327 cubic-inch V8 and pop-up headlights.
Like many concept and engineering vehicles, XP-819 was destroyed, chopped up. Years later, the pieces were found in NASCAR designer and mechanic Smokey Yunick’s garage.
Half Corvette, half Porsche
With a name GM would later recycle on a minivan, the Astro II XP-880 was never publicly identified as a Corvette, but it was one, intended for production in 1970, but never got there. It debuted at the New York auto show, featuring a nose, front fenders and Firefrost Blue paint that that foreshadowed 1970s production cars.
DeLorean, then Chevrolet general manager, asked for a rush program to create a different midengine design to match the midengine Pantera Ford was developing with Italian sports car maker De Tomaso to debut at the 1970 New York auto show. The XP-882 had a tapering body with dramatic fender flares and a louvered rear window like the Mako Shark II concept car. Like so many midengine ‘Vettes before and after, GM brass decided to stick with the tried and true front-engine layout.
Also in the 1970s GM president Ed Cole — another legendary engineer who led the development of the small block V8 and catalytic converter, among other achievements — became enamored with the Wankel rotary engine. Duntov built two midengine experimental ‘Vettes with rotary engines, glad for Cole’s support despite not sharing his enthusiasm for the engine.
Sketching and notes about the Corvette, one of the many originals on display for workers to see at the General Motors Warren Technical Center in Warren, Michigan on Friday, January, 31, 2020 (Photo: Eric Seals, Detroit Free Press)
The 1973 Corvette 2-Rotor XP-987GT was a smaller, European-scale sports car with a rotary engine. The body was all Corvette, but its chassis came from a Porsche 914. Italian design house Pininfarina built its body. GM displayed the 2-Rotor at auto shows in Frankfurt and Paris before the car disappeared, probably sold to a collector.
Bill Mitchell’s most beautiful car
At the same time, Duntov wanted to develop a bigger midengine Corvette. He and Cole hadn’t been on speaking terms since Duntov refused an annual bonus he thought was insultingly small. They made up, at least in part because Duntov wanted a budget to develop what would become the Corvette 4-Rotor Aerovette, an iconic, gull wing design. Duntov believed it was the most beautiful vehicle GM design chief Bill Mitchell oversaw in a career that included the ’57 Chevy Bel Air and ’66 Buick Riviera.
Duntov recycled the XP-882’s chassis for the Aerovette, which featured silver leather interior trim.
A picture of the Aerovette featuring bi-fold gulping doors in the sports car that was never made. It is one of many photographs, drawings and sketches on display on all things Corvette design inside the General Motors Warren Technical Center in Warren, Michigan on Friday, January, 31, 2020 (Photo: Eric Seals, Detroit Free Press)
Despite the car’s striking appearance, Duntov would come to believe his agreement to use a rotary engine was a nail in the midengine ‘Vette’s coffin.
Despite that, another midengine engineering car arrived in 1974. The XP-895 began its life with a steel body. Intrigued by the idea of lightweight materials, DeLorean asked Reynolds Aluminum to create an aluminum body. That cut the car’s weight by nearly 40%, but DeLorean pulled the plug on the project because he wanted a smaller, more European design.
That never happened, and design work on midengine ‘Vettes came to a halt for more than a decade, as GM struggled meeting the challenge of higher fuel prices.
Closing the deal
By 1986, the quest for a midengine Corvette was ready to create another giant figure, and it got one when a young designer named Tom Peters began work on the Corvette Indy concept car. Peters went on to become the chief designer of the sixth- and seventh-generation C6 and C7 Corvettes and play a key role in starting work on the 2020 C8.
With a radically short hood compared to production ‘Vettes and cutting-edge technologies including four-wheel steering, traction control and active suspension, the Indy — so named because it used a 2.65L V8 Chevy developed for Indy Car racing — kept dreams of the midengine ‘Vette alive
The 1990 CERV III — this time the C stood for “Corporate,” not Chevrolet Engineering Research Vehicle — was the next step. Datini’s research convinced him it was an attempt at a production version of the Indy.
CERV III had scissors doors and was built of Kevlar, carbon fiber and aluminum. With a 650-hp twin-turbo 5.7L V8, GM predicted a top speed of 225 mph. It debuted at the 1990 North American International Auto Show in Detroit.
After that, work on the midengine Corvette went undercover for two decades. Photos of disguised prototypes at test tracks surfaced from time to time, but the car seemed to be as much myth as metal. There are whispers the Great Recession halted work on one, setting development back years.
A display of Zora Arkus-Duntov known as “The Godfather of the Corvette” at the General Motors Warren Technical Center in Warren, Michigan on Friday, January, 31, 2020. (Photo: Eric Seals, Detroit Free Press)
Development of the 2020 Corvette Stingray began around eight years ago, a long time for most projects, but the blink of an eye when it’s the last chapter of a 60-year story.
Mark Phelan for Detroit Free Press