The National Hot Rod Association sets exacting standards for each class of car that competes in NHRA-sanctioned drag races. The NHRA features over 200 classes of vehicles divided into 12 categories strictly governed by the NHRA rule makers. The four professional categories that compete in NHRA events are funny cars, top fuel racers, pro stock and super stock cars. Alcohol dragsters and top alcohol funny cars also compete at the professional level.
The size and weight of funny cars is regulated very closely. A funny car can have a wheelbase no longer than 125 inches and no shorter than 100 inches. According to the NHRA, a funny car chassis is made of exactly 179 ¾ feet of 4130 Chromoly tubing and weighs 125 pounds. As of 2010, a typical chassis cost approximately $20,000 and included extra items such as roll cage elements, fuel tanks and parachute-release levers.
Funny car bodies must be styled resembling a 1991 or later two-door coupe or sedan. The body must be a type that was mass-produced by an automobile manufacturer. The body used for funny cars weighs between 87 and 89 lbs. Funny car bodies are made of strong, lightweight materials. The carbon-fiber bodies must be made of a special four-element graphite weave, according to NHRA regulations.
Funny cars are some of the fastest vehicles in racing. They are powered by the same 500 cubic-inch engines used by top fuel dragsters. Most of the funny car teams use an engine that is an aluminum replica of the Chrysler 426 Hemi. The complete engine often costs up to $50,000. The cylinder heads and connecting rods are carved from solid aluminum and the engine uses a supercharger that spins at over 10,000 revolutions per minute. According to the NHRA, these supercharged power plants routinely accelerate funny cars to speeds of over 330 miles per hour.
A funny car does not have a transmission. A special, timer-regulated clutch mechanism transfers the engine's power to the rear wheels in a carefully controlled process. Over a period of three seconds, a hydraulic throw-out bearing and ram applies pressure gradually to the clutch until the engine and drivetrain are matched up. During this process, the clutch can reach temperatures of 1,000 degrees Fahrenheit.