| 1 | Bell / Ganley | Gulf Racing (GB) | | Mirage | M6 | | Ford | S3.0 | 3.0 |
| 2 | Hailwood / Watson | Gulf Racing (GB) | | Mirage | M6 | | Ford | S3.0 | 3.0 |
| 3 | Cevert / Beltoise / Pescarolo | Equipe Matra-Simca (F) | | Matra | MS670 | | Matra | S3.0 | 3.0 |
| 5 | Heinz / McClure / English | Dave Heinz (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.0 | +2.0 |
| 6 | Donohue / Follmer | Penske Racing (USA) | | Porsche | 911 Carrera | RSR | Porsche | S3.0 | 3.0 |
| 7 | Young / Johnson / Fitzgerald | Eddie Johnson (USA) | | Chevrolet | Camaro | Z28 | Chevrolet | T5.0 | |
| 8 | Nehl / Durst | Automotive Engineering Enterprises (USA) | | Chevrolet | Camaro | II Z28 | Chevrolet | T5.0 | |
| 9 | Kessler / Panch / Pickett | Ray Kessler Inc. (USA) | | Chevrolet | Camaro | Z28 | Chevrolet | T5.0 | |
| 10 | Barber / Kemp | Shierson Racing (USA) | | Chevron | B19 | | Ford | S2.0 | 2.0 |
| 11 | DeLorenzo / Carter | Troy Promotions Inc. (USA) | Tony DeLorenzo | Chevrolet | Corvette | C3 | Chevrolet | GT+2.0 | +2.0 |
| 12 | Wisell / de Fierlant / Lafosse | Scuderia Filipinetti (CH) | Georges Filipinetti | Lola | T282 | | Ford | S3.0 | 3.0 |
| 14 | Canada / Christiansen / Tremblay | C. C. Canada (USA) | C. C. Canada | Chevrolet | Camaro | I Z28 | Chevrolet | T5.0 | +2.0 |
| 15 | Keyser / Adamowicz / Beasley | Toad Hall Motor Racing (USA) | Michael Keyser | Porsche | 911 | ST | Porsche | GT+2.0 | |
| 16 | Kirill / Norburn / Bean | Toad Hall Motor Racing | | Porsche | 911 | S | Porsche | GT2.0 | |
| 17 | Gimondo / Dingman | Takondo Racing (USA) | | Chevrolet | Camaro | II Z28 | Chevrolet | T5.0 | |
| 19 | Bartling / Bytzek / Kuehne | Harry Bytzek (CDN) | | Porsche | 908/02 | K Flunder | Porsche | S3.0 | |
| 20 | Jarier / Merzario | North American Racing Team (USA) | | Ferrari | 365 GTB/4 | | Ferrari | GT+2.0 | |
| 21 | Chinetti, Jr. / Grossman / Shaw, Jr. | North American Racing Team (USA) | | Ferrari | 365 GTB/4 | | Ferrari | GT+2.0 | |
| 22 | Migault / Minter | North American Racing Team (USA) | | Ferrari | 365 GTB/4 | | Ferrari | GT+2.0 | |
| 23 | Ballot-Léna / Andruet | North American Racing Team (USA) | | Ferrari | 365 GTB/4 | | Ferrari | GT+2.0 | |
| 24 | van Beuren, Jr. / Rojas / Rebaque | John Buffum (USA) | John Buffum | Ford | Escort | I RS 1600 | Ford | T2.0 | |
| 25 | Everett / Buffum / Pickett | John Buffum (USA) | John Buffum | Ford | Escort | I RS 1600 | Ford | T2.0 | |
| 27 | Shaw / Mosher / Straub | Ernie Shaw | | Ford | Mustang | | Ford | T5.0 | |
| 29 | Noseda / Mummery | Jef Stevens (USA) | | Chevrolet | Camaro | | Chevrolet | GT+2.0 | |
| 30 | Levetto / Levetto / Dube | Guido C. Levetto (USA) | Guido Levetto | Chevrolet | Camaro | Z28 | Chevrolet | T5.0 | |
| 31 | Locke / Bailey | Locke Development Corporation (USA) | James Locke | Porsche | 911 | S | Porsche | GT+2.0 | |
| 33 | McComb / Dooley | John McComb (USA) | | Ford | Mustang | | Ford | T5.0 | |
| 34 | Thompson / Knupp / Murray | Murray Racing (USA) | | Chevrolet | Corvette | C3 | Chevrolet | GT+2.0 | |
| 38 | Muniz / Quintanilla | Quintanilla/Muniz (MEX) | | Porsche | 914 | /6 | Porsche | GT2.0 | |
| 41 | Gage / Grob / Ouellette | Parametrics Systems (USA) | | Lotus | 23 | | BMW | S2.0 | |
| 43 | Helmick / O'Steen / Behr | Dave Helmick (USA) | Dave Helmick | Porsche | 911 | S | Porsche | GT+2.0 | |
| 47 | Chitwood / Chitwood / Nagel | Chitwood Racing (USA) | | Chevrolet | Camaro | Z28 | Chevrolet | T5.0 | |
| 48 | Greenwood / Grable | John Greenwood (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.0 | |
| 49 | Yenko / Johnson / *Greendyke / *Long / *Grable | John Greenwood (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.0 | |
| 51 | Selbert / Schoenfeld / Klempel | Airport Motorsport (USA) | | Porsche | 911 | S | Porsche | GT+2.0 | |
| 52 | Kleinpeter / Gammon / Shelton | Promotion Advertising | | Chevron | B21 | | Ford | S2.0 | |
| 54 | Fitzpatrick / Kremer / Keller | Porsche Kremer Racing (D) | Erwin Kremer | Porsche | 911 | S | Porsche | GT+2.0 | |
| 55 | Lund / Behr / Capps | Tiny Lund | | Pontiac | Firebird | | Pontiac | T5.0 | |
| 56 | Greger / Hild / Schmid | Joest Racing | | Porsche | 911 | S | Porsche | GT+2.0 | |
| 57 | Jöst / Casoni / Blancpain | Reinhold Jöst (D) | Reinhold Jöst | Porsche | 908/03 | | Porsche | S3.0 | |
| 58 | Carduner / Bienvenue | Brumos Porsche (USA) | | Porsche | 911 | S | Porsche | GT+2.0 | |
| 59 | Gregg / Haywood | Brumos Porsche (USA) | | Porsche | 911 Carrera | RSR | Porsche | S3.0 | |
| 62 | Bergstrom / Cook | Bob Bergstrom (USA) | Bob Bergstrom | Porsche | 911 | S | Porsche | GT2.0 | |
| 64 | Baechle / Pierce / Davidson / *Burdick | Weaver Chevrolet (USA) | Ronald Weaver | Chevrolet | Corvette | C3 | Chevrolet | GT+2.0 | |
| 73 | Kreider / Silvers / Toppino | Dale Kreider | | Triumph | GT6 | | Triumph | GT2.0 | |
| 75 | Bock / Shafer / Harrington | Don Winter (USA) | | Chevrolet | Camaro | II Z28 | Chevrolet | T5.0 | |
| 77 | Stone / Jennings / Downs | Silverstone Racing (USA) | George Stone | Porsche | 911 | S | Porsche | GT+2.0 | |
| 78 | Graham / Johnson | J. G. Racing | | Datsun | 240Z | | Datsun | GT+2.0 | |
| 80 | Elliott / McDill | Byron Cook Racing (USA) | | Chevrolet | Camaro | II Z28 | Chevrolet | T5.0 | |
| 84 | Petery / Ziereis | Andy Petery (USA) | Andras Petery | BMW | 2002 | | BMW | T2.0 | |
| 88 | Abate / Cuddy | Edwin G. Abate (USA) | | Porsche | 910 | | Porsche | S2.0 | |
| 89 | Tillson / Holbert / Oest | Holbert Porsche (USA) | | Porsche | 911 | S | Porsche | GT+2.0 | |
| 93 | Fisher / Gloy | Professional Racing | | Chevron | B16 | | Ford | S2.0 | |
| 94 | Ross / Mitchell / Houser | Bolus & Snopes (USA) | | Chevrolet | Camaro | Z28 | Chevrolet | T5.0 | |
| 96 | Rodriguez / Almeida | U.S. Davis Racing | | Chevrolet | Camaro | Z28 | Chevrolet | T5.0 | |
| 99 | Alvarez / Febles | Diego Febles (PR) | Diego Febles | Porsche | 911 | S | Porsche | GT+2.0 | |
| T | Bell / Ganley | Gulf Racing (GB) | | Mirage | M6 | | Ford | S3.0 | |