| 0 | Agor / Nichter | Warren Agor Racing Enterprises, Inc. (USA) | Warren Agor | Chevrolet | Camaro | | Chevrolet | T |
| 1 | Bell / Ganley | Gulf Research Racing Co. (GB) | | Mirage | M6 | | Ford | S3.0 |
| 2 | Hailwood / Watson / *Bell | Gulf Research Racing Co. (GB) | | Mirage | M6 | | Ford | S3.0 |
| 3 | Theodoracopulos / Kwech | Ausca, Inc. (USA) | | Ford | Capri | RS 2600 | Ford | S3.0 |
| 5 | Stewart / Scheckter | Herb Wetanson Racing (USA) | | Ford | Capri | RS | Ford | S3.0 |
| 6 | Donohue / Follmer | Roger Penske Enterprises (USA) | | Porsche | 911 Carrera | RSR 2.8 | Porsche | S3.0 |
| 7 | Felsen / Flickinger / Hagestad | Modern Classic Motors - Ferrari (USA) | | Ferrari | 365 GTB/4 | | Ferrari | GT |
| 8 | Posey / Migault | North American Racing Team (USA) | | Ferrari | 365 GTB/4 | | Ferrari | GT |
| 9 | Grossman / Yenko | Robert Grossman (USA) | Robert D. Grossman | Ferrari | 365 GTB/4 | | Ferrari | GT |
| 10 | Redman / Ickx | Ferrari SEFAC SPA (I) | | Ferrari | 312 PB | | Ferrari | S3.0 |
| 11 | Merzario / Pace | Ferrari SEFAC SPA (I) | | Ferrari | 312 PB | | Ferrari | S3.0 |
| 12 | Schenken / Reutemann / *Ickx | Ferrari SEFAC SPA (I) | | Ferrari | 312 PB | | Ferrari | S3.0 |
| 14 | Holbert / McComb | Holbert's Porsche-Audi (USA) | | Porsche | 911 Carrera | RSR | Porsche | GT |
| 16 | Keyser / Minter | Toad Hall Motor Racing (USA) | Michael Keyser | Porsche | 911 Carrera | RSR 2.8 | Porsche | GT |
| 23 | Monguzzi / Garcia-Veiga | Diagnosis and Service Racing (USA) | | Ferrari | 365 GTB/4 | | Ferrari | GT |
| 25 | Everett / Zeccoli | Bobcor Performance Racing Corp. (USA) | | Alfa Romeo | Montreal | | Alfa Romeo | GT |
| 26 | Kepler / Sharp | Fred Kepler Enterprises (USA) | | Chevrolet | Corvette | | Chevrolet | GT |
| 31 | Jennings / *Locke | Jim Locke (USA) | James Locke | Porsche | 911 | S | Porsche | GT |
| 32 | Beltoise / Cevert | Equipe Matra (F) | | Matra | MS670 | B | Matra | S3.0 |
| 33 | Larrousse / Pescarolo | Equipe Matra (F) | | Matra | MS670 | B | Matra | S3.0 |
| 36 | Miller / Miller | Miller Brothers Racing Enterprises (USA) | | Chevrolet | Camaro | | Chevrolet | T |
| 37 | Miller / Miller | Miller Brothers Racing Enterprises (USA) | | Chevrolet | Corvette | | Chevrolet | GT |
| 41 | Harris / Choiniere | Rodney Harris (USA) | | Chevrolet | Corvette | | Chevrolet | GT |
| 43 | Helmick / O'Steen | Ecurie Escargot (USA) | Dave Helmick | Porsche | 911 Carrera | RS | Porsche | GT |
| 48 | Greenwood / Rutherford | John Greenwood Racing (USA) | | Chevrolet | Corvette | | Chevrolet | GT |
| 59 | Gregg / Haywood | Brumos Porsche-Audi Corp. (USA) | | Porsche | 911 Carrera | RSR | Porsche | S3.0 |
| 63 | Oleyar / *Luebbe | Michael Oleyar (USA) | | Chevrolet | Corvette | C3 | Chevrolet | GT |
| 64 | Baechle / Stahlberg | Weaver Chevrolet (USA) | Ronald Weaver | Chevrolet | Corvette | C3 | Chevrolet | GT |
| 65 | Loomis / Harrison | Gregg Loomis (USA) | | Porsche | 911 Carrera | RSR 2.8 | Porsche | GT |
| 70 | Minter / Harmon | Bob Harmon Racing (USA) | Bob Harmon | Porsche | 911 Carrera | RSR | Porsche | GT |
| 73 | Kuehne / Pechmann | STP March Racing Team (GB) | | March | 73S | | BMW | S2.0 |
| 76 | Downs / Kelly | Silverstone Enterprises (USA) | George Stone | Porsche | 911 Carrera | RSR | Porsche | GT |
| 81 | Egerton / Forbes-Robinson | Pharr West Racing (USA) | Grey Egerton | Porsche | 911 Carrera | RSR 2.8 | Porsche | GT |
| 87 | Jacques Bienvenue | Centrum International Corp. (USA) | | Ferrari | Dino 246 GT | | Ferrari | GT |
| 88 | Carter / DeLorenzo / *Harrison | Carter Racing Services (CDN) | | Chevrolet | Camaro | II | Chevrolet | T |
| 91 | Fisher / Buffum | Professional Racing Associates (USA) | | Chevron | B23 | | Ford | S2.0 |
| 92 | Tillson / *Oest | Holbert's Porsche-Audi (USA) | | Porsche | 911 | S | Porsche | GT |
| 94 | Pickett / Bean | Leidon Blackwell Racing (USA) | | Chevrolet | Corvette | C3 | Chevrolet | GT |
| 97 | Niederer / Larkin | Hans Niederer (USA) | Hans Niederer | Porsche | 911 | | Porsche | GT |