| 1 | Siffert / Bell | J. W. Automotive Engineering Ltd. (GB) | | Porsche | 917 | K | Porsche | S |
| 2 | Rodriguez / Oliver | J. W. Automotive Engineering Ltd. (GB) | | Porsche | 917 | K | Porsche | S |
| 3 | Elford / Larrousse | Martini & Rossi Racing (D) | | Porsche | 917 | K | Porsche | S |
| 5 | Duval / Nicholas / Bailey | Jacques Duval (CDN) | Jacques Duval | Porsche | 914 | /6 | Porsche | GT2.5 |
| 6 | Donohue / Hobbs | Penske/White Racing (USA) | | Ferrari | 512 M | | Ferrari | S |
| 7 | Rand / Blessing | Blessing Racing, Inc. (USA) | Randy Blessing | Shelby | Cobra | | Ford | GT+2.5 |
| 9 | Fleming / Johnson / Barnes | Simone N. Fleming (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 11 | Yenko / DeLorenzo / Thompson | Troy Promotions, Inc. (USA) | | Chevrolet | Corvette | C3 | Chevrolet | GT+2.5 |
| 12 | Thompson / Mahler | Troy Promotions, Inc. (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 14 | Canada / Christiansen | Boykin Auto Repair (USA) | | Chevrolet | Camaro | | Chevrolet | T+2.5 |
| 15 | Keyser / Jennings | Toad Hall Racing (USA) | Michael Keyser | Porsche | 911 | S | Porsche | GT2.5 |
| 16 | Rinzler / Baker | Ring-Free Oil Racing Team (USA) | | Chevron | B16 | | Ford | P2.0 |
| 17 | Fraser / Reynolds / Sage / Baker | Ring-Free Oil Racing Team (USA) | Jim Baker | Chevron | B16 | | Ford | P2.0 |
| 18 | Guthrie / Smith / *Birrell | Ring-Free Oil Racing Team (USA) | | Chevron | B16 | | Ford | P2.0 |
| 19 | Ciccone / Greenhalgh / Roberts | Thomas T. Ciccone, Jr. (USA) | | Chevrolet | Camaro | | Chevrolet | T+2.5 |
| 20 | Gregory / Young | Young American Racing Team (USA) | Gregg Young | Ferrari | 512 M | | Ferrari | S |
| 21 | Chinetti, Jr. / Eaton | North American Racing Team (USA) | Luigi Chinetti, Jr. | Ferrari | 312 P | /71 | Ferrari | P3.0 |
| 22 | Revson / Savage | North American Racing Team (USA) | | Ferrari | 512 M | | Ferrari | S |
| 23 | Bucknum / Posey | North American Racing Team (USA) | | Ferrari | 512 S | Spyder | Ferrari | S |
| 24 | Cluxton / Grossman | North American Racing Team (USA) | | Ferrari | 365 GTB/4 | | Ferrari | S |
| 25 | Andretti / Ickx | Ferrari Automobili (I) | | Ferrari | 312 PB | | Ferrari | P3.0 |
| 26 | Parsons / Weir | North American Racing Team (USA) | | Ferrari | 512 S | | Ferrari | S |
| 28 | Meaney / Wright / Laucks | Ralph Meaney, Inc. (USA) | | Porsche | 914 | /6 | Porsche | GT2.5 |
| 29 | Behr / Conrad / Buffum | Ralph Meaney, Inc. (USA) | Ralph Meaney | Porsche | 914 | /6 | Porsche | GT2.5 |
| 31 | Locke / Everett | Locke Lake Colony & Waterville Estates (USA) | | Porsche | 911 | T | Porsche | GT2.5 |
| 32 | de Adamich / Pescarolo / Vaccarella | Autodelta S.p.a. (I) | | Alfa Romeo | T33/3 | | Alfa Romeo | P3.0 |
| 33 | Galli / Stommelen | Autodelta S.p.a. (I) | | Alfa Romeo | T33/3 | | Alfa Romeo | P3.0 |
| 34 | Vaccarella / Hezemans | Autodelta S.p.a. (I) | | Alfa Romeo | T33/3 | | Alfa Romeo | P3.0 |
| 35 | Wilson / Collins | Collins-Wilson Racing Ent. (USA) | | Chevrolet | Camaro | | Chevrolet | T+2.5 |
| 38 | Quintana / Belperche / Almeida | John P. Belperche (USA) | | Shelby | GT500 | | Ford | T+2.5 |
| 39 | Tisdelle / Kirill | K&T Enterprises (USA) | | Porsche | 911 | T/R | Porsche | T2.5 |
| 40 | Hotchkis / Kirby | Bozzani Porsche, Inc. (USA) | | Porsche | 911 | S | Porsche | GT2.5 |
| 42 | Sereix / Garcia / Noseda | Garcia Racing (USA) | Jose Garcia | Chevrolet | Camaro | II Z28 | Chevrolet | T+2.5 |
| 43 | Garcia / Gonzalez / Mastandrea | Garcia Racing (USA) | | Chevrolet | Chevy II | | Chevrolet | T+2.5 |
| 45 | Pettey / Dutton | Reventlow-Pettey Automobiles (USA) | | Ford | Mustang | | Ford | T+2.5 |
| 46 | Gray / Keller / Magnor | Sebring Racing, Inc. (USA) | | Ford | Mustang | | Ford | T+2.5 |
| 47 | Tremblay / McDill | Bruce Behrens Racing (USA) | | Chevrolet | Camaro | | Chevrolet | T+2.5 |
| 48 | Greenwood / Smothers | John Greenwood (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 50 | Barker / Harrington | John Greenwood (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 51 | Gammon / Donley / *Garza | Waldron Motors Racing Team (USA) | | MG | B | | BMC | GT2.5 |
| 52 | Scott / Lanier / Houser | Waldron Motors Racing Team (USA) | | MG | B | | BMC | GT2.5 |
| 53 | Drescher / Luchette | Marion E. Dickson (USA) | | Ford | Cortina Lotus | | Ford | T2.5 |
| 54 | Arutunoff / Pryor / Goellnicht | Automobiles of Italy, Inc. (USA) | | Abarth | 2000 S | SE010 | Abarth | P2.0 |
| 55 | Clark / Kessler / Kearney | Clearwater Datsun (USA) | | Datsun | 510 | | Datsun | T2.5 |
| 56 | Greger / Weigel | Josef Greger (D) | | Porsche | 907 | | Porsche | P2.0 |
| 57 | Heinz / Johnson / Costanzo | Dave Heinz Racing, Inc. (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 58 | Rahal / Frank / Wise | Nationwide Food Brokers Racing Team (USA) | | Porsche | 906 | | Porsche | S |
| 59 | Gregg / Haywood | Brumos Porsche Audi Corp. (USA) | | Porsche | 914 | /6 | Porsche | GT2.5 |
| 60 | Walker / Springer | Wheel Sport, Ent. (USA) | | Porsche | 911 | S | Porsche | GT2.5 |
| 61 | Kleinpeter / Belcher | Promotional Advertising Corp. (USA) | Hugh Kleinpeter | Lola | T212 | | Ford | P2.0 |
| 63 | Elliott / Gwynne | Preston Hood Chevrolet (USA) | | Chevrolet | Camaro | I | Chevrolet | T+2.5 |
| 64 | Baechle / Luebbe | Bob Baechle (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 66 | Small / Fordyce / *Lipke | Performance Automobile (USA) | | Chevrolet | Camaro | I | Chevrolet | T+2.5 |
| 69 | Howard / Gage | Triton Racing (USA) | | Ford | Escort | I | Ford | T2.5 |
| 71 | Gimondo / Dietrich | Takondo Racing (USA) | | Chevrolet | Camaro | II | Chevrolet | T+2.5 |
| 72 | Mitchell / Kemp | Robert R. Mitchell (USA) | | Chevrolet | Camaro | | Chevrolet | T+2.5 |
| 74 | Rosen / Jacobs | Dr. Mervin B. Rosen (USA) | Merwin Rosen | Porsche | 906 | | Porsche | S |
| 78 | Polimeni / Theall | George W. Sanderson (Sandy's Spares) (USA) | | Volvo | 122 | S | Volvo | T2.5 |
| 80 | Baldwin / Jacob | John T. M. Baldwin (USA) | | Datsun | 510 | | Datsun | T2.5 |
| 81 | Walle / Davey / Reddy | Ray Walle Ent. Inc. (USA) | | Porsche | 911 | S | Porsche | GT2.5 |
| 83 | Montalvo / Garcia / Gómez Mena | German Motors, Inc. & Chem Air Spray, Inc. (USA) | | BMW | 2002 | | BMW | T2.5 |
| 84 | Goldleaf / Taylor / Wheat | Del Taylor (USA) | | Alfa Romeo | 1750 GTV | | Alfa Romeo | T2.5 |
| 86 | Gottlob / Lowther / *Nagel | Cliff Gottlob (USA) | Cliff Gottlob | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 88 | Oliver / Maynard / Flanagan | S-Car-Go-Racing (USA) | | Chevrolet | Camaro | I | Chevrolet | T+2.5 |
| 89 | Gafford / Smith | H. Houghton Smith (USA) | | Chevrolet | Camaro | | Chevrolet | T+2.5 |
| 92 | Cordts / Pike | B. F. Goodrich Tire Co. (USA) | | Chevrolet | Camaro | | Chevrolet | T+2.5 |
| T | Jo Siffert | J. W. Automotive Engineering Ltd. (GB) | | Porsche | 917 | K | Porsche | S |