The Real McCoy

Also from Issue 58

  • Lingenfelter Supercharged C6
  • Interview: Ken Lingenfelter
  • Road trip: 2010 Grand Sport coupe
  • 1996 LT4 coupe
  • Market Report: C4
  • Special-order 1967 big blocks
  • Racing: GT2-class C6.R race car
  • How To: C5 headlight gear replacement
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With these adjustments, Duntov reported, “The car goes where it is pointed, and does so without hesitation. On turns taken hard, it does not plow or skid, but gets into a drift. If the right amount of power is fed, the drift can be maintained without danger of the rear end getting presumptuous and assuming the position of the front.”

The kind of handling that Duntov described wouldn’t have been possible without the extensive changes that took place under the hood. The new 265 cubic-inch V8 weighed 41 pounds less than the ’55 version. This improved weight distribution, resulting in a 52/48 front/rear balance. Cylinder-head changes squeezed the thick end of the wedge-shaped chamber closer around the spark plug, increasing the compression ratio from 8.0:1 to 9.25:1. Atop the heads were special finned die-cast aluminum rocker covers.

New cast-iron exhaust manifolds with central outlets had larger-capacity internal passages, while tougher exhaust valves were specified. Ignition at higher crank speeds was improved by the use of a twin-breaker distributor, while the steel shielding for the ignition wiring was much improved over the provisional ’55 arrangement. With the single Carter four-barrel carburetor and the special cast-iron inlet manifold designed for use with it, peak power was up 15 horsepower to 210 at 5,200 rpm. This rose to 225 bhp at the same speed with twin four-barrel Carters connected by a progressive linkage on an aluminum manifold. Torque with this version was 270 lbs-ft at 3,000 rpm.

The new engine was a spectacular improvement, yet even more significant to most sports-car enthusiasts was the adoption of a three-speed manual transmission as standard equipment. It was driven by a clutch with a dozen coil springs instead of the diaphragm-spring type used earlier. Inside the standard passenger-car three-speed housing were a new clutch shaft and gear, new countershaft gears and a new second gear to give the remarkably close ratios of 1.31:1 in second and 2.20:1 in low gear. Arkus-Duntov had in fact argued in favor of an even higher bottom gear, 1.83:1, but had been overruled.

Axle ratios were 3.55:1 as standard and 3.27:1 as an option with the manual gearbox. Other ratios were readily available because the 1956 Corvette had a new rear axle that was more closely related to that of the latest passenger car, with better support for its pinion shaft and differential. The brakes themselves weren’t changed, but were given linings more resistant to fade and wear. This rounded out the improved specification of a transformed sports car.

The 1956 Corvette was the last of its breed to be styled entirely on the tenth floor of the downtown Detroit New Center building, before GM Styling’s move to magnificent new quarters at the Saarinen-designed GM Technical Center in Warren, Michigan. When the decision was made to continue Corvette production, relatively little time remained to make drastic appearance changes. Nevertheless, every aspect of the original body was altered and refined.

At the rear, the protruding taillights were shaved off and replaced by inset lights. Though there was a suggestion to have the exhaust pipes exit through the sides of the rear fenders—as shown on the 1954 Motorama Nomad—the production version had rear outlets, as recommended by the engineering department.