On the surface, NHRA Pro Stock cars appear to closely resemble production-based showroom vehicles, but underneath the brightly colored sheet metal, they are in fact, all out race cars capable of 6.5-second quarter-mile elapsed times and speeds of over 212-mph. The body styles most often found in Pro Stock includes the current model Pontiac GXP, Chevrolet Cobalt, Ford Mustang, and Dodge Avenger. In order to maintain a stock appearance, aerodynamic modifications in Pro Stock are limited to a single 14-inch rear spoiler, and a hood scoop, which not only feeds additional air into the massive twin four-barrel carburetors, but is necessary for engine clearance.
Unlike Top Fuel dragsters and Funny Cars, which use exotic nitromethane fuel, superchargers, and fuel injection, Pro Stock entries must burn high octane racing gasoline and are limited to a pair of four-barrel carburetors. Pro Stock engines can also be no larger than 500-cid, and each car can weigh no less than 2,350 pounds, with driver. A competitive Pro Stock engine produces close to 1,400 horsepower and revs to more than 11,000 rpm.
The technology and the attention to detail that goes into building a state-of-the-art Pro Stock engine is virtually unmatched in all of motorsports. It can take hundreds of hours to prepare a single set of cylinder heads or an intake manifold and most successful Pro Stock teams devote the majority of their resources to the area of engine development. Although lightweight engine components and exotic metals are banned, virtually anything else is legal in a Pro Stock engine as long as it maintains its original two-valve per cylinder configuration and does not exceed the 500-cubic inch maximum.
All the power in the world isn’t much good if it can’t be applied to the race track, which is why a substantial amount of development also goes into building a Pro Stock chassis. Underneath the body, a modern Pro Stock car features a fully-sprung four-link rear suspension, adjustable electronic shock absorbers, and spring-loaded wheelie bars. The roll cage not only protects the driver in the event of an accident, but also serves as an integral part of the chassis.
It has often been said that a Pro Stock car is one of the most difficult cars to drive in all of drag racing. Indeed, Pro Stock drivers stay plenty busy during each six-second run. Beginning with a carefully orchestrated pre-race procedure that includes a tire heating burnout, a Pro Stock driver carefully inches his car to the starting line. Reacting to the first hint of a yellow light from the Christmas tree, the driver quickly releases the clutch pedal and then must make four separate gear shifts. Each shift must be perfectly timed in order for the car to achieve maximum performance. As if staging, leaving the starting line and shifting wasn’t enough, a Pro Stock driver must also concentrate on keeping the car as straight as possible during the run before finally deploying the twin parachutes which slow the car from over 212-mph at the end of each quarter-mile run.
