America's Most Powerful

But the most exciting home for the new-age DOHC V-8s is the Mustang Cobra. Suddenly, the character and nature of the ponycar is redefined; the engine wings its way to redline eagerly instead of struggling for air like Sir Edmund Hillary reaching the top of Everest. The distinction between the Camaro Z28 SS and Mustang Cobra isn't in raw acceleration, it's in how they get there: The 305-horsepower, 16-valve Camaro produces epic low- and midrange torque, while the 305-horse, 32-valve Mustang does its power play with adequate off-the-line urge and a wondrous sprint to the upper end. Both are satisfying, yet unlike the other in their feel.

Ultimately, despite the millions of man-hours spent optimizing every element of the internal-combustion engine over the past century, a good one is still only about 25-percent efficient at transforming the potential heat energy in gasoline into mechanical energy. That means that as reliable and powerful as America's engines have become, there's still room for improvement.

Dodge Viper RT/10Previous-generation Vipers made 400 horsepower at 4600 rpm. To beat the EPA's drive-by noise test, Dodge neglected to mention that an additional half dozen or so horses were available at 600 rpm higher. For '96, a new, quieter rear-exiting exhaust system allows Dodge to get credit for all 415 horses at 5200 rpm. Plus, new spark tuning and fuel calibration help further boost torque (which wasn't underrated as far as we know) by 26 to 488 pound-feet. Converting this into forward motion is a challenge: Launching at much over 1700 rpm results in serious wheelspin, while much under 1800 rpm bogs the motor. But it does strike with the venom expected of America's most power-ful car. It can not only overwhelm its own tires, but the tires on the car next to it as well. New features for '96 include a removable hard top, sliding rigid plastic side windows, a more robust differential, stronger drive shafts, aluminum suspension control arms, and revised spring and shock rates.