Each racing category has its distinctive competitive goal, each with its own design rules. The rules dictate vehicle specifications such as engine size, overall weight, body style, chassis arrangement, dimensional restrictions, and permitted technical add-ons. American racing has become codified in these rules, but the rules are always changing. The history of American racing and the wide diversity in forms of racing can be traced through the changing rules.
The rules sometimes changed for technical reasons, and sometimes for economic reasons. Some sets of rules are ordained by closely held governing bodies. Other sets of rules are established by elected governing boards or by larger, national or international organizing bodies (similar in structure to Olympic governance). In every case, however, the power to set rules comes from those who own the tracks or have the most money supporting the competitions.
Any set of codified rules creates a particular design envelope within which creative and well-funded players continually press limits, seek better design of component parts, and sometimes find a technical avenue not anticipated in the rules and thus prevail. By its nature, racing is out-and-out competition—technological as well as on the track.
Throughout racing history, changes in the rules—for engine size, supercharging (or banning thereof), chassis details, overall sizes and styles, fuel capacities—were frequent. Usually, when one participant or racing team started to dominate their races, those who collectively had more sponsorships at risk or who owned the tracks saw to it that the rules were changed to better equalize the chances of winning. Then the cycle began again.
