The first race was held in 1974 and was called the AFM 300.
The race was held on Ontario Motor Speedway’s 3.2-mile road course, which, much like Daytona International Speedway, utilized part of an oval Superspeedway and an infield road-course section. Ontario, which ran from 1974 to 1980 in the spring, attracted many of the top riders and teams in the then burgeoning ranks of Superbike racing. It was America’s own version of the Suzuka 8 Hours, if you will. the American Federation of Motorcyclists (AFM) 6 Hours-had a seven-year run and, in spite of annual scoring faux pas, it became the best-known endurance race in America.
