October 12, 1962
In the eight years after the Chevy small-block V-8 became available in '55 Corvettes, the two-place sports car had established a strong reputation in competition. While Chevrolet was busy denying
Its racing involvement to the Automobile Manufacturers Association, which in 1957 had banned all forms of factory-backed competition, Zora Arkus-Duntov was busy preparing four of the first-to-be-built, all-new '63 Sting Rays for road racing. On the weekend of October 12, 1962, the world was suddenly made aware of the new Corvette and a never-before-offered "Special Performance Equipment" option package, as the four new racers made their debut in the three-hour, 250-mile Los Angeles Times Grand Prix at Riverside International Raceway. When the dust had settled, three of the four new Vettes had been sidelined due to mechanical failures, but the fourth-driven by Doug Hooper-took the checkered flag. On its initial outing, the '63 Z06, based on an entirely new platform and hurriedly prepped for racing, beat out Europe's finest (and the new Shelby Cobra) and forever establish America's Sports Car as a powerful force to be reckoned with on the track.
The 1963 Z06
Although Chevrolet observed the AMA's ban on competition, there was no way to pull the racer out of Zora's blood. RPO Z06, the Special Performance Equipment Package, assembled a collection of goodies to put the production Sting Ray at the top of the racing food chain. As the Godfather himself put it, "Suitably equipped and set up, the new Corvette promises a potential that is hard to equal or surpass by even the world's costliest cars."
At $1,818.45 the Z06 package alone cost nearly half the base price of a split-window coupe, but for die-hard performance enthusiasts, there was no way to put a price tag on a factory showroom-stock race car-especially one sporting the brutish power of America's finest V-8 for the time. The fuel-injected L84 solid-lifter 327 with 11.25:1 compression and 360 horsepower was ordered in over 2,400 "normal" Corvettes in '63, but it was only one of the numerous mandatory options (How's that for an oxymoron?) tied into the Z06 package, along with some special, heavy-duty Z06-specific items. In lieu of the standard, smooth-shifting Borg-Warner T10 four-speed transmission, all Z06s were equipped with a beefier Muncie four-speed. A heavy-duty 1-inch front anti-sway bar replaced the standard 7/8-inch one, and much-stiffer-than-normal springs and shocks were factory installed at all four corners. An extremely stiff seven-leaf rear spring replaced the standard nine-leaf model in the new independent rear suspension, which also featured Posi-traction limited slip as part of RPO Z06.
Perhaps the most unusual component of the Z06 package, however, were the "Competition Brakes." Since four wheel discs would not be available on a Corvette until 1965, the Z06 exhibited the best Duntov could do to make a drum-braked car ready for sports car competition, especially when disc brakes were already prevalent in Europe. Larger and stronger-than-standard Al-Fin power drum brakes with sintered metallic linings maximized the stopping power of the less-than-cutting-edge technology. The heavy-duty finned cast-iron brake drums measured 1 1/2-inches wide with a diameter of 11 13/64-inches (standard drums were 11 inches), creating 334.3 square inches of total sweep compared to 328 square inches for conventional drums. A unique Kelsey-Hays master cylinder and a Morraine power booster controlled these big drums. Special brake self-adjusters worked while rolling forward because race cars spend very little time in reverse. In addition, the Z06s received ventilated front and rear backing plates and a unique 24-blade cooling fan for both front and rear drums. For extra cooling, external air scoops for the front brakes were left in the cars as they left the assembly line, to be installed by the dealers later.
All Z06s were originally slated to receive fiberglass enduro-style, 36.5 gallon fuel tanks, but only 63 ended up with them. Likewise, cast aluminum knock-off wheels were intended to be standard, but also became a victim of "production complexities." Knock-off wheels were available through dealer parts departments. Even though the Z06 package was expensive and ill-suited for street use, the majority of the 199 street-legal race cars produced were ultimately sold for exactly that.