The second year of IROC competition took place over three weekends in 1974 and 1975. IROC II saw the use of the Chevrolet Camaro in all races, which replaced the Porsche Carrera RSR race cars used in the first year of competition. The only track carried over from the first year was Riverside International Raceway, as the series raced on the oval at Daytona International Speedway instead of the infield road course. Michigan International Speedway was also added as the second oval in the schedule, which consisted of four races. Bobby Unser was the series champion, and took home $41,000 for his efforts.
The roster of drivers and final points standings were as follows:
| Position | Driver | Winnings | Series |
|---|---|---|---|
| 1 | Bobby Unser | $41,000 | USAC Champ Car |
| 2 | A. J. Foyt | $27,600 | USAC Champ Car |
| 3 | Cale Yarborough | $22,200 | NASCAR Winston Cup |
| 4 | Bobby Allison | $20,400 | NASCAR Winston Cup |
| 5 | Emerson Fittipaldi | $18,300 | Formula One |
| 6 | David Pearson | $16,500 | NASCAR Winston Cup |
| 7 | George Follmer | $15,300 | SCCA |
| 8 | Ronnie Peterson | $12,300 | Formula One |
| 9 | Johnny Rutherford | $9,900 | USAC Champ Car |
| 10 | Richard Petty | $6,000 | NASCAR Winston Cup |
| 11 | Graham Hill | $5,400 | Formula One |
| 12 | Jody Scheckter | $4,500 | Formula One |