Season results
Overall winners in bold.
| Rnd | Circuit | Over 2.0 Winning Team | Under 2.0 Winning Team | Results |
|---|---|---|---|---|
| Over 2.0 Winning Driver(s) | Under 2.0 Winning Driver(s) | |||
| 1 | Mexico City | #99 Aztec Racing | Werner Frank | Results |
 Moisés Solana
|
 Werner Frank
| |||
| 2 | Riverside | #6 Roger Penske Racing | #60 Otto Zipper | Results |
| Mark Donohue
|
Don Wester
| |||
| 3 | Laguna Seca | #6 Roger Penske Racing | #33 Otto Zipper | Results |
| Mark Donohue
|
Scooter Patrick
| |||
| 4 | Bridgehampton | #26 Carl Haas Racing | #66 Werner Frank | Results |
| Skip Scott
|
Werner Frank
| |||
| 5 | St. Jovite | #6 Roger Penske Racing | #37 Altona Motors | Results |
| Mark Donohue
|
 Horst Kroll
| |||
| 6 | Kent | #26 Carl Haas Racing | #4 Porsche | Results |
| Skip Scott
|
Lew Florence
| |||
| 7 | Watkins Glen | #6 Roger Penske Racing | #88 Werner Frank | Results |
| Mark Donohue
|
Werner Frank
| |||
| 8 | Road America | #26 Carl Haas Racing | #12 C.L. Phillips | Results |
| Skip Scott Chuck Parsons
|
Cliff Phillips Al Cervenka
| |||
| 9 | Mid-Ohio | #6 Roger Penske Racing | #69 E.L. Hall | Results |
| Mark Donohue
|
Mike Hall
|