| 1 | Siffert / Bell | J. W. Automotive Engineering (GB) | | Porsche | 917 | K | Porsche | S |
| 2 | Rodriguez / Oliver | J. W. Automotive Engineering (GB) | | Porsche | 917 | K | Porsche | S |
| 3 | Marko / Lins | Martini & Rossi Racing Team (D) | | Porsche | 917 | K | Porsche | S |
| 4 | Elford / van Lennep | Martini & Rossi Racing Team (D) | | Porsche | 917 | K | Porsche | S |
| 5 | Duval / Nicholas / Bailey | Sun Oil Company (CDN) | Jacques Duval | Porsche | 914 | /6 | Porsche | GT2.5 |
| 6 | Donohue / Hobbs | Penske-White Racing (USA) | | Ferrari | 512 M | | Ferrari | S |
| 8 | Nehl / Perry | American Racing Promotions (USA) | | Porsche | 911 | S | Porsche | GT2.5 |
| 10 | Walle / Sherwin | Walle Enterprises (USA) | | Porsche | 911 | S | Porsche | GT2.5 |
| 11 | DeLorenzo / Yenko / Mahler | Owens Corning Fiberglass (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 12 | Thompson / Mahler | Owens Corning Fiberglass (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 14 | Canada / Hines, Jr. / Pickett | Boykin Auto Repairs (USA) | | Chevrolet | Camaro | Z28 | Chevrolet | GT+2.5 |
| 15 | Kirill / Tisdelle | K&T Enterprises (USA) | | Porsche | 911 | T/R | Porsche | GT2.5 |
| 16 | Keyser / Beasley / Jennings | Toad Hall Racing (USA) | Michael Keyser | Porsche | 911 | S | Porsche | GT2.5 |
| 17 | Gimondo / Dietrich | Tokondo Racing (USA) | | Chevrolet | Camaro | Z28 | Chevrolet | T |
| 18 | Meaney / Bean / Wright | Ralph Meaney (USA) | | Porsche | 914 | /6 | Porsche | GT2.5 |
| 19 | Behr / Buffum / Kremer | Ralph Meaney (USA) | Ralph Meaney | Porsche | 914 | /6 | Porsche | GT2.5 |
| 20 | Gregory / Young / *Cannon | Young American Racing/North American Racing Team (USA) | | Ferrari | 512 M | | Ferrari | S |
| 21 | Garcia-Veiga / Chinetti, Jr. / De Cadenet | North American Racing Team (USA) | | Ferrari | 312 P | | Ferrari | P |
| 22 | Revson / Posey / Parsons / Chinetti, Jr. | North American Racing Team (USA) | | Ferrari | 512 M | | Ferrari | S |
| 23 | Bucknum / Adamowicz / *De Cadenet | North American Racing Team (USA) | | Ferrari | 512 S | Spyder | Ferrari | S |
| 26 | Gosselin / de Fierlant | Jacques Swaters (B) | | Ferrari | 512 S | | Ferrari | S |
| 28 | Merzario / Juncadella | Escuderia Montjuich (E) | | Ferrari | 512 S | Spyder | Ferrari | S |
| 31 | Everett / Locke / Netterstrom | Locke Lake Colony (USA) | | Porsche | 911 | T | Porsche | GT2.5 |
| 33 | McComb / Tullius | John McComb (USA) | | Ford | Mustang | | Ford | T |
| 35 | Wilson / Collins | Collins-Wilson Racing Ent. (USA) | | Chevrolet | Camaro | | Chevrolet | T |
| 36 | Matzen / Heyser / Sears | Racing Specialties Co. (USA) | | Ford | Mustang | | Ford | T |
| 37 | Johnson / Mims / Wetzel / Nagel | Yenko Sportscars, Inc. (USA) | | Chevrolet | Vega | | Chevrolet | T |
| 38 | Fleming / Johnson / Barnes | Simone N. Fleming (USA) | | Fiat | 124 | Sport Coupé | Fiat | T |
| 40 | Hochreuter / Bartling / *Petermann / *Brezinka | Fritz Hochreuter (CDN) | | Porsche | 911 | | Porsche | GT2.5 |
| 41 | Taylor / Goldrich / Dyer / Goldleaf | Del Taylor (USA) | Del Taylor | Alfa Romeo | 1750 GTV | | Alfa Romeo | GT2.5 |
| 42 | Garcia / Sereix / Small | Garcia Racing Jose M. Garcia (USA) | | Chevrolet | Camaro | Z28 | Chevrolet | T |
| 43 | Hanrioud / Sage | Jean-Pierre Hanrioud (F) | | Chevron | B16 | | Ford | P |
| 44 | Hindson / Noah / Bunker | Art Bunker (USA) | | Porsche | 911 | T | Porsche | GT2.5 |
| 45 | Baker / Grossman / Brown / Reynolds | Baker Motor Company (USA) | Jim Baker | Chevron | B16 | | Ford | P |
| 46 | Rinzler / Christian / Fraser / Baker | Baker Motor Company (USA) | Jim Baker | Chevron | B16 | | Ford | P |
| 47 | Tremblay / McDill / Beatty | Bruce Behrens Racing (USA) | | Chevrolet | Camaro | | Chevrolet | T |
| 48 | Dobkin / Maynard / Oliver | S-Car-Go-Racing (USA) | | Chevrolet | Camaro | | Chevrolet | T |
| 50 | Greenwood / Barker / Lang | John Greenwood (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 51 | Gammon / Donley / Garza | Waldron Motors Racing Team (USA) | | MG | B | GT | BMC | GT2.5 |
| 52 | Scott / Lanier / Houser | Waldron Motors Racing Team (USA) | | MG | B | GT | BMC | GT2.5 |
| 55 | Clark / Kearney | Clearwater Datsun (USA) | | Datsun | 510 | | Datsun | T |
| 57 | Heinz / Costanzo | David Heinz Racing, Inc. (USA) | | Chevrolet | Corvette | C3 | Chevrolet | GT+2.5 |
| 59 | Gregg / Haywood | Brumos Porsche Audi Corp (USA) | | Porsche | 914 | /6 | Porsche | GT2.5 |
| 64 | Luebbe / Baechle / Orr | Robert Luebbe (USA) | | Chevrolet | Corvette | | Chevrolet | GT+2.5 |
| 65 | Rhindress / Clark | Homeline Corp. (USA) | | Lancia | Fulvia | HF | Lancia | GT2.5 |
| 70 | Belperche / Davidson | William A. Davidson (USA) | | Triumph | GT6 | | Triumph | GT2.5 |
| 72 | Mitchell / Kemp | Robert R. Mitchell (USA) | | Chevrolet | Camaro | | Chevrolet | T |
| 73 | Lewis / Fairbrother | Robert E. Lewis (USA) | | Ford | Cortina | GT | Ford | T |
| 74 | Straub / Brown | Al Straub (USA) | | Ford | Mustang | | Ford | T |
| 75 | Pettey / Bock | Reventlow-Pettey Automobiles (USA) | | Ford | Mustang | | Ford | T |
| 77 | Marcus / Dent | Grand Prix Motors (USA) | | BMW | 2002 | | BMW | T |
| 79 | Lawrence / Moore / Bishop | Danny L. Moore (USA) | | Shelby | GT350 | | Ford | T |
| 80 | Lieb / Drolet / Daroff | Fred Lieb (USA) | | Dodge | Dart | | Dodge | T |
| 81 | Tillson / Oest / Junco | Dieter R. Oest (USA) | | Lancia | Fulvia | HF Rallye | Ford | T |
| 87 | Elliott / Gwynne | Preston Hood Chevrolet (USA) | | Chevrolet | Camaro | | Chevrolet | T |
| 88 | Mastandrea / Lilly | Norberto Mastandrea (USA) | | Chevrolet | Camaro | Z28 | Chevrolet | T |
| 89 | Brimble / Smith | H. Houghton Smith (USA) | | Chevrolet | Camaro | | Chevrolet | T |
| 91 | Noseda / Nunez / *Stevens / *Mummery | Larrauri Racing (USA) | | Chevrolet | Camaro | Z28 | Chevrolet | T |
| 92 | Cordts / Pike | B.F. Goodrich Tire Co. (USA) | Jerry Titus | Pontiac | Firebird | | Chevrolet | T |
| 93 | Whitaker / Tunstall / Reed | Donald S. Wright (USA) | | Volvo | P1800 | | Volvo | GT2.5 |
| 97 | Stumes / Cummings | Susan Trumbull Cummings (USA) | | Shelby | GT350 | | Ford | T |
| 98 | Matthews / Savage / Ongais | Ed Matthews (USA) | | Ford | Mustang | | Ford | T |
| T | Rodriguez / Oliver / Siffert / Bell | J. W. Automotive Engineering (GB) | | Porsche | 917 | K | Porsche | S |
| T | Vic Elford | Martini & Rossi Racing Team (D) | | Porsche | 917 | K | Porsche | S |