Trans Am rules require that vehicles to be constructed with a purpose-built tube frame chassis. The bodies are made of composites, such as carbon fiber, Kevlar and fiberglass. The rules stipulate that the cars should maintain the recognizable external features of the manufacturer's model while providing flares necessary to keep the tires inside the bodywork. SCCA Pro Racing uses body templates to ensure the shape of cars was within designated tolerances. Cars are required to use the stock windshield or an approved alternative, which has to be mounted in the original location and at the original angle. The rules also dictate the use of the stock taillights, which are often the only production parts on the vehicles. All cars are required to use an American-based engine. The rules allow a 335 cubic inch or 358 cubic inch 9:1 V8 engines with a car weight of 2700-lbs. Another choice is a V6 with a 275 cubic inch engine weighing 2500-lbs. But the most popular choice was a 310 cubic inch motor. All options must be fitted with a 4150 Holley carburetor.

The fifteen race season began in March on the Streets of Phoenix, followed by the purpose-built road course at Sears Point International Raceway. Next, drivers compete on temporary circuits at Addison, Texas and Detroit. Then teams travel to the west coast for an event at Portland International Raceway. Rounds six and seven sees the series are conducted on temporary layouts at Cleveland, Ohio and De Moines, Iowa. In August, the championship visits Watkins Glen International, Trois-Rivieres in Quebec, Canada and Denver, Colorado. Next on the schedule are three of North America’s most popular road courses Mosport Park, Mid-Ohio Sports Car Course and Road America. The championship ends on November 4 in St. Petersburg, Florida.

Round twelve of the 1990 SCCA Pro Racing Trans Am Series was held at Mosport Park. Drivers would compete in a fifty-lap contest around the ten turn 2.459-mile road course.