While the tuner cars battled to see who could hit the highest top speed on our course, the stock production cars had a slightly different fight. For the stockers, we set a lower top speed — 120 mph, a speed all three cars were capable of attaining. So the winner was determined by lowest elapsed time.
We invited three production cars, all with more than 400 horsepower: a 460-hp Dodge Viper ACR, a 405-hp Corvette Z06, and a 415-hp Porsche 911 Turbo. All three rode on stock tires set at their recommended pressures.

We also allowed each manufacturer to send a driver, and surprise! the manufacturers sent us a trio of highly talented drivers. Porsche sent three-time Le Mans winner and long-time Porsche driver Hurley Haywood. Chevy sent hard-charging John Heinricy, GM North America's director of vehicle dynamics and a successful production-car racer. And finally, Dodge called in Tommy Archer, a veteran Viper driver on the international sports-car circuit.
The production cars would suffer a problem or two also. On the way to the track, the Viper's clutch quit. A visual inspection did not suggest a quick fix, so another Viper was dispatched from the home office in Auburn Hills. It arrived three hours later in the middle of a rainstorm that would continue for the rest of the day. So unfortunately, Archer and the Viper didn't get a chance to join the intense Porsche-Chevy war that was waged throughout the morning.

The common thinking at the staging area was that the Porsche's all-wheel-drive system would help it overcome its less-advantageous power-to-weight ratio. The Porsche's twin-turbocharged flat-six thumps out 10 more horses than the Corvette's newly fortified 405-hp V-8, but the Chevy has the substantial advantage of being 375 pounds lighter.
The Porsche squirted off the line quicker, as we figured it would, to 30 mph. But when the needle touched 60, the svelte Vette opened up a 0.1-second gap that would only widen as acceleration continued. Heinricy is also so well practiced in production Corvettes (most of Haywood's time has been spent in Porsche race cars) that he snicked off clutchless upshifts as if he were in a finger-shifting Formula 1 racer.

If we thought the Porsche would have the edge in straight-line acceleration, we weren't sure what would happen on the road course. The best Corvette Z06 we've tested outperformed the 911 Turbo on the skidpad (0.98 g versus 0.93 for the 911) and in braking tests, stopping from 70 mph in 152 feet, 11 feet shorter than the Porsche can manage. But again, we thought the four-wheel-drive Porsche would squirt out of corners quicker. Any advantage the Porsche's driveline provides wasn't enough, however, as the Vette pulled higher grip in almost every corner and finished the road-course portion sooner by 1.9 seconds.
Haywood, however, was able to maximize the Porsche Turbo's traction and exit the road course about 5 mph faster, erasing some of the road-course deficit during the final sprint to 120 mph. But as the speeds increased, the Vette's lower drag coefficient (0.29 versus 0.31) gave it yet another edge, and it finished the full course a slimmest-of-slim 0.7 second sooner. It was a photo finish every race spectator hopes to see. —Larry Webster