AC Delco 150

The AC Delco 150 was an ARCA Racing Series stock car race held at Flat Rock Speedway, in Ash Township, Michigan. Without NASCAR support, the track struggled in the late 1950s. In 1960, new general manager Joan Simmons created a points system and raised competitor numbers, leading to track attendance increasing by 81 percent. A year later, Simmons formally established ties with France's friend and MARC head John Marcum, who became track owner the following year. Marcum would later rename his sanctioning body the Automobile Racing Club of America (ARCA), whose Bondo/Mar-Hyde Series continued racing at Flat Rock until 2000, with Frank Kimmel winning the final ARCA premier series race at the track. Simmons remained in her position until 1970. Following Marcum's death in 1981, wife Mildred and grandson John Drager took over track operations; when John departed for other interests, brother Ron became track promoter.

History
Flat Rock Speedway was constructed in 1952, but financial issues led to the original investors backing out. Under Sheldon Hayes of the Cadillac Asphalt Company, the track was completed in 1953; using 70 tons of a mixture of rubber and asphalt, Hayes created a "rubberized" asphalt surface that was the first of its kind for a race track. The speedway opened on August 14. It was initially scheduled to open on August 7, but the opening was postponed by a week after a raccoon drowned in its drainage system and subsequent rain flooded the track.

Dick Good won Flat Rock's first track championship in the "Hardtop" division, which was rebranded as the Late Model class in 1954. That year, NASCAR founder and president Bill France Sr. became its promoter and helped attract NASCAR drivers like Curtis Turner, Joe Weatherly, and Lee Petty to the track. France left his position at the speedway in 1956. Motor City Speedway promoter Andy Barto served as Flat Rock's promoter until he stepped down in March 1956 and was replaced by Hayes, who was the track president, to commit his work to Motor City; Barto returned to Flat Rock as its general manager in 1959.