One More Year
Chevrolet originally planned to introduce the all-new, Mako Shark II-based third-generation Corvette in the '67 model year, but the new car just wasn't quite ready in time. So the second-gen model hung on for one more year. That didn't mean, though, that Chevy made do with a carry-over '66 Vette. No, Duntov and his crew made enough changes to vault the '67 model from mere epilogue status to a car that is widely considered the best of the C2 generation.
Externally, the badges were shaved off the fenders, the hood script also disappeared, and a new set of fender louvers -- five louvers raked forward -- gave the car a more purposeful look. This year marked the first appearance of the five-slot steel Rally wheel, while the optional multi-blade cast-aluminum wheel lost its knock-off hub and bolted on conventionally. A new "stinger" hood was used on big-block models, some with stripes that either matched or complemented the car's interior color.
Under that stinger hood beat a 427-inch heart, but Chevy's powertrain engineers yet again upgraded the big-cube mill. The '66 L72 gave way to the L71, which replaced the single four-barrel with three Holley two-barrel carbs. Tri-power induction had been a mainstay of GM muscle cars for years, and in the Vette it boosted the 427's rated output to 435 hp. (An L68 version of the 427, essentially the L36 with triple carbs, was rated at 400 hp.)
But Duntov wasn't yet finished with the 427. Late in the model year came the L88, which topped the Mark IV four-bolt block with aluminum cylinder heads that offered big intake and exhaust ports and, working with the forged aluminum pistons, squished the compression ratio up to 12.5:1. A high-rise aluminum intake manifold was home to an 850-cfm Holley carb, which was topped by an unusual-looking air-cleaner assembly that sealed to the stinger hood (made functional for L88 applications). Again, Chevrolet conservatively rated the L88's output at 430 hp, but its actual power peak was likely more than 500 hp.
The L88 was intended as a race-only option, and it came with the M22 "Rock Crusher" Muncie four-speed, heater and radio deletes, heavy-duty suspension, Positraction, and metallic brakes. Just 20 Corvettes were sold with the L88 option in '67, and many of these early cars were plagued with connecting-rod failures, a design flaw that was fixed for the '68 model year.
The C2 was the shortest-lived Corvette generation of them all, yet the cars produced during those seminal years truly brought the marque up to world-class sports car status. By the close of C2 production, the Corvette was able to run with the best Europe had to offer, and it finally made Duntov proud.
Z06 and Grand Sport Officially, Chevrolet adhered to the ban on factory support of racing instituted by the Automobile Manufacturer's Association. But Zora Arkus-Duntov, a hot rodder and racer to the core, would not be denied. He circumvented the ban as best he could, offering full-race parts for private buyers and also developing competition cars despite the corporation's no-race edict.
In the fall of 1962, as Chevrolet unveiled the first of the '63 Corvettes, Duntov made ready RPO Z06, an option package that would turn the Corvette into a SCCA production-class racer. It included stiffer springs and shocks; a bigger front sway bar; and a dual-circuit, vacuum-assisted brake package with ducts, scoops, and holes designed to keep the brakes cool. A 36.5-gallon fuel tank was initially part of the Z06 package, as were knock-off wheels, but both were deleted from the package a few months later (though the tank was still available as a stand-alone option). "Mandatory options" with the Z06 included the 360-horse fuel-injected L84 small-block, close-ratio four-speed, and Positraction axle.
Just 199 Z06 coupes were built. It was an expensive option for the time, with a $1,818 price tag that was more like $2,500 with the mandatory options factored in. The Z06 also had a hard time keeping up with Carroll Shelby's Cobras, which were quite a bit lighter.
Duntov had Shelby in his sights when he proposed a lightweight competition version of the '63 Vette that would become known as the Grand Sport. Based around a tubular frame, the Grand Sport featured super-thin fiberglass bodywork (with giant wheel openings to clear fat racing tires), a reinforced version of the production IRS, and disc brakes at all corners. Though initial plans called for the Grand Sports to be powered by a 377-inch aluminum small-block, the engine wasn't ready for the car's debut, so the cars first raced using an all-aluminum version of the fuel-injected 327.
Duntov had grand plans for the Grand Sport, hoping that 125 would be built. But just five were finished before GM's brass clamped down and forbade further production or development. Before the hammer fell, though, three of the Grand Sports raced at the Nassau Speed Week in 1963 and handily beat Shelby's Cobras. The five then went to privateer racers, with two losing their roofs in an effort to improve their aerodynamics.
In the end, the Grand Sports weren't afforded enough development time to live up to their potential, potential that was lost when GM opted to follow rules that other factories ignored.