Duntov’s Last Corvette Racer Kit

In 1974, Zora Arkus-Duntov was one year away from GM’s mandatory retirement age of 65. Twenty-one years before, Zora saw Harley Earl’s Corvette at the 1953 Motorama and later said that it was the most beautiful car he’d ever seen. It’s what motivated him to seek employment at GM. The only job he was interested in was to be an engineer on the Corvette. Knowing that his time at GM was limited, Duntov wanted to do one last Corvette “racer kit.”

The L88 racer kit, and later the all-aluminum 427 ZL1, was a huge success that brought a lot of racing glory to Corvettes from 1967 through the early ’70s. It was also a time of tremendous advancements in racing technology. Road racing cars were running on tires that were unimaginable just 10 years before. The factory L88 flares were adequate, but the tires were getting too big for the big fender bulges. In the early ’70s, John and Burt Greenwood were the lead guys in Corvette racing, taking the cars into the realm of “purpose-built” race cars. Many were asking of the Greenwood cars, “It looks like a Corvette, but besides the engine, where’s the Corvette?” Ever the innovator, John Greenwood suggested to Duntov that a widebody kit could be developed that would cover the widest tires and generate additional downforce. Enter Duntov’s final “racer kit” —the widebody.

Duntov called it his “silhouette racer” and set Randy Whittin at GM Design to the project. The front fenders were wedge-shaped and fanned out to the front edge of the doors. The rear fenders were also wedge-shaped and ballooned into large pontoon shapes, large enough to cover 20-inch-wide slicks. An adjustable wing was added to the back for additional downforce. Whereas in the early ’60s race car designers were concerned with reduced frontal area, with massive amounts of horsepower and huge sticky tires, “downforce” was the new objective. With huge racing tires, broad shoulder fenders, and a deep front air dam, the look was beyond menacing. Diversified Glass Company made the prototype parts and the widebody kit was included in the Chevrolet Power Manual. Greenwood then contracted with Diversified and started selling body kits as part of his burgeoning Corvette race car business.

Of course, it all starts with an engineering prototype. While not an all-out race car like the ’69 car, it was close enough to make the troops stand back! The mule car was based on a production ’74 Corvette and was powered by a balanced and blueprinted cast-iron ZL1 variant with open-chamber heads, header side pipes, a big Holley double-pumper carb, and the L88 cold-air induction hood. Clear plastic headlight covers over quartz-iodine headlights were used and oil coolers were behind the mesh-covered front grille openings. The body kit parts were riveted to the stock body and the seams covered over with 200-mph duct tape. Lowered and wearing magnesium racing wheels and tires, this was one bad-ass-looking Corvette with that “cobbled together” look.

Marty Schorr (founder and first editor of Vette magazine) was the editor of CARS magazine at the time. As the editor of a popular enthusiast magazine and partners with Joel Rosen’s Baldwin Motion Super Cars enterprise, Marty had a nice working relationship with Duntov. One day while visiting Duntov in Detroit, Marty got a ride in Zora’s latest and last Corvette beast. As Marty tells the story, “One day, he took me out on the high-speed oval test track. We were going full-tilt, with the tail slightly out, while he had a cigarette in his mouth, explaining suspension geometry and big-block engine development! He had great control of this animal car. He was so ‘out there’ that many times he was banned from the test track.”

There was no published record of the prototype’s performance, and aside from CARS magazine and later Vette Quarterly (Vette magazine’s original name) Duntov’s “silhouette racer” got little attention, but the Greenwood brothers “Batmobile” sure did. Overnight, almost all road racing C3 Corvettes were wearing the widebody kit. Greenwood’s Sebring ’75 Corvette holds the official all-time highest speed on the banking at Daytona International Speedway of 236 mph, set on February 2, 1975. And what of Duntov’s engineering prototype? Like Zora’s white ’69 ZL1, it was never seen again after 1974. Most likely, the good parts were removed and the rest sent to the crusher. While the car holds a prominent place in this series of experimental and prototype Corvettes, because it had so little attention and is so relatively unknown, to date there have been no published reports of a replica in the making. Attention builders! Here’s an opportunity for you!

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