The Racecar

Each racetrack or sponsoring organisation maintains a rule book outlining each class of racecar; including dimensions, engine size, equipment requirements and prohibitions. The requirements for each class are usually coordinated with other racetracks and associations to allow for the widest available venue for each type of car. This coordination allows the drivers to enter many different racetracks, increasing their chances of winning; allows the racetrack to field as many cars as possible; lets the racing associations develop a series of race events; and promotes fan interest.

Many fans prefer one or the other of the different type cars. Open wheel fans say, "Real racecars don't have fenders." Stock car fans point out that even minimal contact between open wheel racers usually disables both cars. In reality, both types of vehicles have weak and strong points. Open wheel racers are usually lighter and nimbler. Stock cars can push and shove their way to advancement.

Many tracks support both types of racer in their programmes. Both types range from powerful V8 engines to small, still powerful, 4-cylinder engines. Some of the smaller open wheel racers even have classes for single-cylinder powerplants. Depending on the class, the cars may have wings to aid in handling at higher speeds.

Open Wheel Cars

Open wheel cars are generally manufactured with tubular frames and a body purchased for that particular class. Classes include:

Dwarf (5/8 replicas of 1928 to 1948 coupes and sedans)
Kart (Go Kart)
Sprint
Midget (Speedcar)

The sanctioning bodies include:

USAC - The United States Automobile Club
World of Outlaws Spring Cars

Modified Cars

Modified cars are a hybrid of open wheel cars and stock cars - this class of car has the racing characteristics of a stock with the real wheels covered by fenders and the front wheels open. There are sanctioning bodies that control the rules for this class at most tracks. The sanctioning bodies include:

NASCAR (National Association of Stock Car Automobile Racing)
IMCA (International Motor Contest Association)
DIRT (Drivers Independent Race Tracks)
UMP (United Midwest Promoters) - which was purchased by DIRT in December 2004

Stock Cars

Stock cars are generally automobiles manufactured by the major automakers with certain modifications as allowed for each class. There are several general types:

Non-production cars (These are stock cars custom built for racing, usually with welded tubular frames and custom built or purchased bodies)
Super Late Model- Usually welded tubular frame over fibreglass body with a variant of a Chevrolet engine.
Super Late Model engines: Most all are variants of Chevrolet engines, and most start with an aluminium 350 C.I. Chevy block with stroker crank, high flow degreed aluminium cylinder heads and high-flow exhaust headers. Engines are capable of 750 HP and redline at 9,500 RPM. Cubic Inch Displacement for the engines can range from the basic 358 C.I. small block up to the 430 C.I. Big Block Chevy.
Modified production cars (These cars are modified manufactured automobiles. They have the interiors and glass stripped out, a racing seat and roll cage installed, and various other safety features added. The engines are modified as allowed by the different rulebooks):

Factory Stock
Mini Stock
Pro Stock
Hobby Stock
Stock Car
Pure Stock
Street Stock

Unmodified production cars (These cars are automobiles just as driven on the street; including the original interiors. The engines may be modified as allowed under different rules):