[1] These cars were typically procured directly from dealerships, with minimal alterations made to meet the demands of the racetrack.

The affordability and accessibility of stock cars allowed racing enthusiasts from all walks of life to participate, contributing to the growth and popularity of the sport.

Drivers started customizing their vehicles by enhancing performance and safety features, such as reinforcing chassis frames, installing roll cages, and improving engines and suspension systems.

These modifications allowed the stock cars to withstand the intense demands of racing, turning them into formidable competitive machines.

[2] These modifications increased the cost to compete, and in order to attract new competitors, race promotors responded by adding new divisions for "lesser modified" passenger cars.

[3][4] Requirements for these introductory divisions can vary greatly, but all are based on a full-bodied passenger vehicle and an original equipment manufacturer (OEM) production engine.

[5][7] The Sport Compact (IMCA, DIRTcar) or Pure Stock (NASCAR) or Mini-Stock or Bomber divisions are the lowest entry-level racing class.

[23] The National Hot Rod Association (NHRA) promotes a "Stock " class in the U.S. and Canada where virtually any car is eligible to compete, and entries are classified using a system that divides factory shipping weight by a horsepower factor.

Engines must be correct for the make and model vehicle and must retain stock cylinder heads, intake manifold, and carburetor.

[27] Every September at Mid-Michigan Raceway in Stanton, hosts the Pure Stock Muscle Car Drag Race.