Many of us gazed longingly at the Superformance Corvette Grand Sport at this year’s SEMA show. Sitting pretty in the Lingenfelter booth, the car makes your imagination run wild. What would it be like to sit in the driver’s seat and feel the 550-horsepower monster with 500 lb-ft of torque pushing your body back in the seat? Lucky for us, Hillbank Motorsports in Irvine, CA hooked us up with a test drive of this ferocious ‘Vette.
American-owned, South African manufacturer Superformance, is known world-wide for their amazing Cobra replicas and Shelby-licensed production of continuation Cobras. Now, they seized the opportunity to recreate one of the rarest and most heralded cars in history: the legendary Corvette Grand Sport (under license to GM) — in concert with chassis maker Duntov Motors, who build the racecar versions.
The Corvette GS, amongst motorsports aficionados, is racing royalty. Its lineage goes back to a time when the Big Three had embargoed “racing activities”, and much of the high performance came out of secret performance “skunkworks” collaborations between the OEMs and third parties. In 1955, the tragedy at the 24 Hours of LeMans led several manufacturers to pull back on racing support. The accident saw a magnesium Mercedes, piloted by Pierre Levegh fly into the crowd on the main straightaway, breaking into pieces and killing the driver and 86 spectators. The U.S.-based OEMs, on a handshake agreement in 1957, vowed to stop factory racing efforts, and became known as the AMA ban.
Even so, all three OEMs still quietly supported third party teams who continued in NASCAR, sports cars, and IndyCar racing — despite the agreement. At GM, Zora Arkus-Duntov, a Belgian-born engineer specializing in high-performance and racing, had joined the company in 1953. Duntov, Harley Earl, and Bill Mitchell were still developing the Corvette, which was having immense success in the sports car racing circles.
The C2, soon to be known as the “Sting Ray,” would be undergoing development as a street car, but behind the corporate curtain, there were racing versions in the works. The “Q” Corvette concept was inspired by a young designer named Peter Brock, who was directed by Mitchell in his visions of a Mako Shark he had caught while deep sea fishing. The street version of the C2 was penned by designer Larry Shinoda, based on the Mako-Q prototype.
Shortly after joining General Motors, Duntov wrote a memo to his bosses called “Thoughts Pertaining to Youth, Hot Rodders and Chevrolet.” Call it the best laid plans for the future of Chevrolet performance. Capitalizing on Duntov’s idea, Chevy created one of the most successful performance parts programs in the industry. Duntov joined GM after seeing the first Corvette at Motorama in 1953 and offered his services, which at that time were in-demand as he had his hands on Talbot-Lago, Allard, and the Porsche 550 RS Spyder in both development and as a race driver.
By 1962, now as Corvette’s chief engineer, Duntov started on a program to produce a lightweight racer based on a prototype of the new 1963 Corvette. Similarly, Ford had begun working with Carroll Shelby in developing the first Cobras — which would begin to dominate racing and take the fight successfully to the C1 Corvettes. Duntov’s program planned to build and homologize 125 Grand Sport Corvettes to make them eligible for international GT racing. During the process, which was kept top-secret, GM executives got wind of the project and the program was cancelled. In the end, only five cars were built, and GM ordered the cars destroyed — luckily they were sent out the back door.
The cars competed and were driven by greats including Roger Penske, A.J. Foyt, Jim Hall, and Dick Guldstrand. Dick Thompson was the first driver to take the checker in a Grand Sport at Watkins Glen on August 24, 1963. He was driving chassis number 4.
The Corvette Grand Sports had several different engines, with the most notable being a 377 cubic-inch displacement, all-aluminum, small-block with four Weber side-draft carburetors and a cross-ram intake from the factory. It was rated at 550 hp. Our test drive GS, sported a Ligenfelter built GM Performance LS3 with a Borla eight Stack Cross Ram Electronic Fuel injection, producing 525 hp — a modern interpretation of a classic!
On the original GS, the body panels were made of thin fiberglass to reduce weight, and the structure was made from aluminum rather than steel. The ladder frame was made from large seamless tubular steel side members connected front and rear with cross-members the same size.
The same can be said of the era new GS. The hand-laminated fiberglass body is aesthetically and dimensionally correct to the original. The tubular frame construction done by Superformance is exactly modeled after the lightweight chassis. Like the original, this GS has a fully independent front and rear suspension with half-shafts, but this version is built by Superformance.
Superformance will sell you a roller version of the car optioned like this example for $125,000. Options include side pipes, black-painted knock off wheels (with spinners) and tires, air-conditioning, and power windows. This allows you to install whatever drivetrain you would like.
One of the early versions had a tuned, Cadillac Northstar engine. We really like the Ligenfelter LS3. The base roller is $99,000. Essentially you can go as crazy or as close to original as you want. All the cars are eligible for the GM Corvette Grand Sport Registry. The engine, as we drove it, will run you an other $36,000, bringing the completed package to $161,765. That’s an absolute bargain for this street legal, track-ready monster of a car. Considering what one of the “original 5” will run — if you can even convince a current owner to part with it!
An outboard differential oil cooler, which completes the iconic look, is also available. It can be functional or ornamental. In the case of our car, it was nonfunctional, but looked really cool and racy. The deep blue paint, including roundels and pin striping, accentuated the genuine Grand Sport look.
Driving the car was a true throwback to the early C2s. Above and beyond the amount of power, the feel was pure ‘60s Corvette. Our journey this time was not around a race track — which surely would have been a treat — but on the streets and roads surrounding Superformance in Irvine and Lake Forest, California (a few nice roads there). Regardless, we were able to really feel the car and experience it in traffic, though I imagine fighting for the first corner in traffic might be the preferable experience for a car like this.
Some years ago, my uncle had a ’65 big-block that he kept for less than four weeks before selling it, claiming “it was like driving a racecar on the street.” Making it a very undesirable daily. I guess the same could be said for the GS — however, I would probably still drive it as much as possible, even to get the groceries! There is a trunk, and it would be roomy enough for a few bags from the store. Because of all the attention it gets, as a consideration, I would not be apt to leave it in a well travelled parking lot. The car actually felt reasonably well mannered, even at low engine RPM, and did well on the Irvine boulevards, playing the role of “just another commuter.” The clutch is heavy though, and that might tire out the driver, but you get used to it pretty quick.
As mentioned, it really has the driving feel of a period car. The steering wheel had some play, as did the brake pedal. As a matter of fact, the first 500 yards down the street, I caught myself pumping the brakes, thinking there was no brake pressure. Once I understood that the brakes really began to engage about half way to the floor I could work with them. The big vented Wilwoods, which are standard on the car, get the car slowed like throwing an anchor out the window. The Tremec T-56 Magnum six speed transmission was fluid and smooth as I shifted throughout the gears.
Now let’s talk about the loud pedal.
This car gets up and goes with a Chevy small-block growl that was music to the ears. The car has no radio — and a darn good thing too — as it would be superfluous. The baritone song this car makes as the speed comes on is what sensationalists call “orgasmic.” Yep. It’s all that!
Because of the play in the steering wheel, tracking the car through a corner takes a bit of learning, particularly for those of you who have tight-steering, modern ‘Vettes. But the big tires and custom crafted shocks put plenty of rubber on the road, making the car handle nicely through corners with plenty of steering feedback.
Needless to say, our experience behind the wheel was amazing! Both Dave and I chortled with glee at the roar and acceleration, as it was probably as close as either of us were going to get to driving a real Grand Sport. If Duntov, Mitchell, and Earl were around today, I am certain they would be very proud of the Superformance version of their very secret and iconic steed.