Goodyear Radial Challenge), and later as Champion Spark Plug Challenge. The initial race held was in 1969 at Talladega Superspeedway Road Course. Gaston Andrey was first overall in an Alfa Romeo Giulia Super sedan. The Series' first year was actually 1970 with only two races, the inaugural race was at the newly constructed Summit Point Motorsports Park on Memorial Day weekend; Rasey Feezell was first overall in an Alfa Romeo Giulia TI Super sedan; the second race was held at the Montgomery Speedway, Alabama, Red Farmer won in a specially prepared Datsun 510. Feezell didn't fare too well having to drive against the local four-cylinder "beater class" cars brought in to fill out the field, with their protruding wheels rubbing Racey's "immaculate" Alfa Romeo. Infuriated, Feezell quit and never ran another IMSA RS race after that. The idea was to attract racers who did not have the budgets that were required in the GT category as well as an emphasis on compact sedans such as the AMC Gremlin and the Opel Manta. There were two classes from 1970 through 1973: Class A for under two liters and under 1.6 liters with overhead cam and Class B for over 1.6 L with overhead cam and over two liters up to the largest permitted engine being the AMC Gremlin. In 1974 all cars were placed in one class, with the only parity for the smaller engines being free carburetion for under 1.6 liters. Limited preparation was permitted, and since the entrants were meant to be street-driven race cars, the original rules required the retention of headlights, seats, upholstery, window cranks, stock brakes and original springs and radial tires. Only the exhaust systems and shock absorbers were free. Later rules regarding headlights, seats, upholstery, window cranks, original springs, and other stock elements were loosened up somewhat. From the beginning, engine modifications similar to Sports Car Club of America B Sedan were permitted, with the main difference being that over-boring cylinders was not allowed, and stock carburetors being required, but modifications allowed. The series was loosely based on rival SCCA Trans-Am's Two-Five Challenge rules. The series became dominated mostly by Mazda's rotary-powered RX-2 and RX-3 prompting IMSA to specify heavier weights than piston-engined cars and prohibited any modifications to the rotors and more importantly to intake and exhaust ports. Datsun also had a fair share of success within the series with cars such as