Surrounded in turbulent times, the saga of the 1963 Corvette Grand Sport started in early 1962 with the code name “Lightweight.” The goal of lightening—by 1,100 pounds—over the standard production Corvette Sting Ray was to attain overall victory at FIA GT endurance races with the emphasis on winning the 24 Hours of Le Mans.
In order to meet the FIA’s homologation regulations Chevrolet was required to build 125 Grand Sport Corvettes, but only five cars were completed before—in accordance with a 1957 Automobile Manufacturing Association ban on racing—GM brass caught wind of Duntov’s top secret program and pulled the plug. In wisdom typical for the era, GM brass ordered the five Grand Sports to be destroyed, but Zora Arkus-Duntov was able to get three into the hands of privateers and hide the other two.
In the 21st century wiser heads prevail at General Motors and there’s a proper respect for Corvette racing heritage. The General has lent its full support for GM-licensed replicas to be built using the original Grand Sport molds and design blueprints to bear the Corvette Grand Sport name. The Superformance Corvette Grand Sport is a true continuation of a 1963 model that incorporates most of the milestones in drivetrain and engineering progress found in a new Corvette. For starters, the Superformance edition is fully street legal and in bespoke form can be custom ordered from a palette of custom colors or painted from a chart of era-correct color and stripe combinations.
The manufacturing of complete Corvette Grand Sport rollers sans engines and transmissions is done in Port Elizabeth, South Africa, in a 300,000 square-foot facility. A factory so high-tech, Duntov would be amazed at the CNC equipment situated amongst highly skilled craftsmen producing the cars by hand. The Corvette, since its introduction in 1953, has been made from three different varieties of resin composites enthusiasts still refer to as fiberglass.
The Superformance Corvette Grand Sports, using improved molds derived from the original Corvette factory molds, are made to stricter dimensions that produce less waves and tighter door and hood gaps. The fiberglass is hand laid up in the molds exactly as in 1963, four layers of fiberglass strand mat and then topped with two layers of Coremat. Superior to the single-stage Magic Mirror acrylic lacquer applied in 1963, the continuation Superformance Grand Sports are sprayed using Glasurit two-stage acrylic urethane and then color sanded and rubbed out. The results appear in a show-quality Concours d’Elegance finish.
What appears to be a trunk lid on the original five 1963 Grand Sports is an access lid to service the IRS differential. On the Superformance Grand Sport the exact shaped trunk lid is in place, but it covers a relatively spacious trunk. Impressively, the IRS on the Superformance is a period-correct style Duntov C2/C3 locker. Large Wilwood four-wheel disc brakes replace the sintered metallic drum brakes as fitted in 1963. There’s a choice of three different wheel designs and a selection of high-performance tires to choose from. The only difference between the tubular aluminum chassis on the 1963 Grand Sport and the Superformance chassis is steel is used on the latter. So instead of weighing 1,100 pounds lighter than a 1963 production Corvette the Superformance Grand Sport weighs 900 pounds less.
Interior design decisions include choosing between a spartan race interior and the touring interior package that includes German leather throughout. Available options include power windows and door locks with period correct switches and genuine Vintage Air air conditioning. A barrier of sound deadening thermocoustic insulation laid beneath plush bound carpet holds the cold and keeps the heat. Superformance commissioned Classic Instruments of Boyne City, Michigan, to custom replicate gauges authentic to the point of a bent tachometer and speedo needle.
It was an experimental, all-aluminum block racing engine powering the Grand Sport Corvettes in 1963: a 377-inch small-block producing 550 horsepower. Under the hood the Superformance Grand Sport Corvette offers an array of Chevrolet Performance Connect & Cruise engine choices paired with either a manual or automatic transmission. The sky is the limit when it comes to available horsepower, ranging all the way up to Lingenfelter Performance Engineering’s latest and greatest offerings.
The engine and transmission in the car featured is an LT4 with a T-56 Super Magnum six-speed transmission installed by Vlado Jancev and his team at V’s Performance in Orange, California. If an automatic transmission is preferred the eight-speed 8L90E is paired with the LT4.
As of December 2017, there have been over 30 Superformance Grand Sport Corvettes produced. The prices start at $109,900 sans engine and transmission, and thanks to the “Low Volume Motor Vehicle Manufacturers Act of 2015,” hopefully one day Superformance will offer turnkey examples on its dealer network’s showroom floors. And remember, it’s not a kit car, it’s a factory-authorized continuation of the real deal, civilized with modern improvements. Vette
Photos by Jorge Nunez