| 1 | Caldwell D7 Chevrolet | Autodynamics Corporation | white (+blue) | | | | open | mid |
| 2 | McLaren Elva Mark II Chevrolet | Autodynamics Corporation | white (+blue) | | | | open | mid |
| 4 | McLaren M6A Chevrolet | McLaren Cars Limited | orange | McLAREN CARS/STP | Goodyear | Valvoline | open | mid |
| 5 | McLaren M6A Chevrolet | McLaren Cars Limited | orange | McLAREN CARS/STP | Goodyear | Valvoline | open | mid |
| 6 | Lola T70 Mk.3B Chevrolet | Roger Penske Racing Ent. | | SUNOCO SPECIAL | | Sunoco | open | mid |
| 7 | Lola T70 Mk.3B Chevrolet | Team Surtees Limited | | | | | open | mid |
| 10 | Mirage Mark I B Chevrolet | Jack Nethercutt | plum | | | | open | mid |
| 11 | Lola T70 Mk.3 Chevrolet | Peyton A. Cramer, Dana Chevrolet | red | DANA | Goodyear | Valvoline | open | mid |
| 12 | Lola T70 Mk.2 Chevrolet | Pacesetter Homes | yellow | PACESETTER HOMES | | | open | mid |
| 13 | McLaren Elva Mark II Chevrolet | Morley Racing Team | | | Goodyear | | open | mid |
| 14 | McLaren Elva Mark II Chevrolet | Skip Barber | | | | | open | mid |
| 15 | Matich SR3R Repco Brabham | Frank Matich Pty. Ltd. | | | | | open | mid |
| 16 | Lola T70 Mk.2 Chevrolet | Roger Penske Racing Ent. | dark blue (+yellow) | SUNOCO SPECIAL | Firestone | Sunoco | open | mid |
| 17 | Honker II Ford | Paul Newman/Holman & Moody, Inc. | purple | Paul Newman's/Holman Moody/STP | Firestone | | open | mid |
| 21 | Lola T70 Chevrolet | Smothers Bros. Racing Team | dark blue (+white) | | Goodyear | | open | mid |
| 22 | McLaren Elva Mark IIB Chevrolet | Ecurie Soucy Racing Team | white (+red) | Soucy | Goodyear | Valvoline | open | mid |
| 24 | McKee Mk.7 Chevrolet | Robert J. Nagel | | | | | open | mid |
| 25 | McKee Mk.7 Oldsmobile | Ralph Salyer | dark blue (+white) | THE SMOTHERS BROTHERS | Goodyear | | open | mid |
| 26 | McLaren Elva Mark III Chevrolet | Carl Haas Automotile Imports, Inc. | white | SIMONIZ | Goodyear | Valvoline | open | mid |
| 27 | McLaren Elva Mark II Chevrolet | | | | | | open | mid |
| 28 | McLaren Elva Mark II Ford | Ecurie Greene, Inc. | | | | | open | mid |
| 32 | Ferrari 412 P Spyder | North American Racing Team | red | STP | Goodyear | | open | mid |
| 36 | Lola T70 Mk.3B Ford | All American Racers, Inc. | | | | | open | mid |
| 37 | McLaren Elva Mark III Chevrolet | Donald J. Morin | darker | | | | open | mid |
| 39 | McLaren Elva Mark II Chevrolet | Heimrath Racing | orange | BARDAHL SPECIAL | | | open | mid |
| 52 | Lola T70 Mk.3 Chevrolet | Peyton A. Cramer, Dana Chevrolet | white | DANA/SUNRAY DX SUPER SPORT | Goodyear | Sunray Oils | open | mid |
| 57 | McLaren Elva Mark III Chevrolet | David G. Billes | green | STP | | | open | mid |
| 66 | Chaparral 2G Chevrolet | Chaparral Cars | white | | | Shell | open | mid |
| 76 | Lola T70 Mk.3 Chevrolet | Webster Racing Enterprises | dark blue (+red) | | | | open | mid |
| 78 | Lola T70 Mk.2 Chevrolet | Friedkin Ent., Thomas Friedkin | metallic blue | FRIEDKIN RACING | Goodyear | Valvoline | open | mid |
| 79 | Lola T70 Mk.2 Chevrolet | Greenville Racing | dark green | | | | open | mid |
| 91 | McLaren Elva Mark III Chevrolet | Drummond Racing Organization | silver (+red) | | | | open | mid |