| 0 | Field / Ongais / Minter | Interscope Racing (USA) | Ted Field | Porsche | 935 | K3/80 | Porsche | GTX | +2000/Gr.5 |
| 00 | Field / Ongais / Minter | Interscope Racing (USA) | Ted Field | Porsche | 935 | /77A | Porsche | GTX | |
| 01 | Roehrig / Laurin / White | Roehrig Racing (USA) | J. Kurt Roehrig | BMW | 320 | i | BMW | GTU | |
| 03 | Frank / *Bartling / *Pallavicini | Toyota Village (USA) | Werner Frank | Porsche | 934 | | Porsche | GTO | |
| 05 | Akin / Woods / Rahal | Racing Associates (USA) | Charles Mendez | Porsche | 935 | K3 | Porsche | GTX | |
| 06 | DiBattista / Ciccone / Howes | Intrepid, Inc. | | Porsche | 911 | | Porsche | GTU | |
| 07 | Heimrath / *Moran / *Rutherford | Heimrath Racing (CDN) | Ludwig Heimrath | Porsche | 935 | | Porsche | GTX | |
| 08 | Speer / Ratcliff / Wolters | Moran Construction (USA) | | Porsche | 911 | SC | Porsche | GTU | |
| 09 | Paul / Holbert / *Henn | Thunderbird Swap Shop (USA) | Preston Henn | Porsche | 935 | /77A | Porsche | GTX | +2000/Gr.5 |
| 2 | Jöst / Stommelen / Merl | Liqui Moly (D) | Reinhold Jöst | Porsche | 935 | J | Porsche | GTX | +2000/Gr.5 |
| 3 | Busby / Jenner / Knoop | Jim Busby Racing (USA) | Jim Busby | BMW | March M1 | | BMW | GTX | IMSA GTP |
| 4 | Finotto / Facetti / *Ricci | Jolly Club (I) | | Lancia | Beta Montecarlo Turbo | | Lancia | GTX | -2000/Gr.5 |
| 5 | Mendez / Redman / Miller | Racing Associates (USA) | Charles Mendez | Porsche | 935 | K3 | Porsche | GTX | |
| 6 | Fitzpatrick / Schurti / Barbour | Dick Barbour Racing (USA) | Dick Barbour | Porsche | 935 | K3/80 | Porsche | GTX | |
| 8 | Beasley / Grantham / Stone | Bob Beasley (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 9 | McKitterick / Garretson / Verney | Dick Barbour Racing (USA) | Dick Barbour | Porsche | 935 | K3 | Porsche | GTX | |
| 10 | Heinz / Wellik / Young | Oftedahl Trucking (USA) | Gordon Oftedahl | Chevrolet | Camaro | II | Chevrolet | GTO | |
| 11 | Korten / Neve / Grob | March Engineering (GB) | | BMW | March M1 | | BMW | GTX | IMSA GTP |
| 12 | Smith / Johnson / Schoepflin | Sidney Smith III | | Porsche | 914 | /6 | Porsche | GTU | |
| 13 | Forbes-Robinson / Townsend / Meister | Andial Racing (USA) | Randolph Townsend | Porsche | 935 | K3 | Porsche | GTX | |
| 14 | Dieudonné / Koechlin / Walger | Renaissance Group Racing (USA) | Stanton/Barbour | Porsche | 935 | | Porsche | GTX | |
| 15 | Gebhardt / Beilcke / *Trieb | Bavarian Motors International | | BMW | 3.5 CSL | | BMW | GTO | |
| 16 | Mason / *Yenko / *Thompson | Yenko Chevrolet-Honda | Don Yenko | Chevrolet | Corvette | C3 | Chevrolet | GTO | |
| 17 | Bohren / *Aase / *Kline | Racing Beat | | Mazda | RX-7 | | Mazda | GTU | |
| 18 | Arutunoff / *Marina / *Drolsom | Automobile International (USA) | Anatoly Arutunoff | Lancia | Stratos | HF | Ferrari | GTU | |
| 19 | Cord / Adams / *Ferguson | Chris Cord Racing (USA) | | Chevrolet | Monza | | Chevrolet | GTX | |
| 22 | Bruckmann / Goodell / Cunningham | Group Bruckmann | Volker Bruckmann | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 23 | Devendorf / Davenport / Carney | Frank L. Carney (USA) | Frank Carney | Datsun | 280ZX | | Datsun | GTU | |
| 24 | Refenning / Mummery / Tilton | American Racing Team (USA) | Glen Kolil | Porsche | 934 | | Porsche | GTO | |
| 25 | Miller / Cowart / Beckers | Deren Automotive (USA) | | BMW | M1 | | BMW | GTX | |
| 28 | Nehl / Kirill / Rude | Tom Nehl (USA) | | Chevrolet | Camaro | II | Chevrolet | GTO | |
| 30 | Moretti / *Cazzaniga / *Canepa | Electrodyne (I) | Gianpiero Moretti | Porsche | 935 | J | Porsche | GTX | |
| 32 | "Jamsal" / Pineda / Barrientos | Scorpio Racing (ES) | | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 33 | Aten / Welter / Refenning | A-10 Racing | Richard Aten | Porsche | 911 | | Porsche | GTU | |
| 35 | Taylor / Ramsey / Provenzano | Janis Taylor | | Alfa Romeo | Alfetta GTV | | Alfa Romeo | GTU | |
| 37 | Espinosa / Cortes / Lopez | Botero Racing (CO) | Luis Botero | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 38 | Fernandez / Ferrer / Nierop | Boricua Racing (PR) | | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 39 | Moffat / Johnson / Fisher / *Frisselle | JLC Racing | | Mazda | RX-7 | | Mazda | GTU | |
| 42 | Neland / Ferran / Cotrone | Dick Neland (USA) | | Chevrolet | Camaro | | Chevrolet | GTO | |
| 44 | Tullius / McComb / Kelly | Group 44 (USA) | | Triumph | TR8 | | Rover | GTO | |
| 46 | DeNarvaez / Naon / Londono | DeNarvaez Racing (CO) | Mauricio DeNarvaez | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 49 | Henderson / Demele / Copeman | Tortilla Flats Racing (USA) | Bob Copeman | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 51 | Kirby / Hotchkis / Hotchkis, Jr. | Moana Corp. | John Hotchkis | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 52 | Hamilton / Cripe / Snow | Snowmobile Racing | Fred Snow | Porsche | 911 | S | Porsche | GTU | |
| 54 | Garcia / Vadia / Herman | Montura Racing (USA) | Tony Garcia | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 55 | Kent-Cooke / Bleynie / Ballot-Léna | Racing Associates (USA) | Charles Mendez | Porsche | 935 | | Porsche | GTX | |
| 56 | Borlase / Kravig / Hammond | Rick Borlase | | Porsche | 911 Carrera | | Porsche | GTO | |
| 57 | Baker / Gilliland / Scott | Independent Personalized (USA) | Wayne Baker | Porsche | 914 | /4 | VW | GTU | |
| 58 | Febles / *Soldevilla / *Gonzalez | Coco Lopez-Pina Colada | Coco Lopez | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 59 | Gregg / Haywood / Leven | Brumos Porsche Audi (USA) | Peter Gregg | Porsche | 935 | /79 | Porsche | GTX | |
| 62 | Koll / Cook / LaCava | William J. Koll (USA) | | Porsche | 914 | /6 | Porsche | GTU | |
| 63 | Northam / Davenport / *Thomas | Guy Thomas (USA) | | Chevrolet | Camaro | | Chevrolet | GTX | |
| 65 | Morton / Adamowicz | Nicholas/McRoberts Racing | Nicholas/McRoberts | Ferrari | 365 GTB/4 | | Ferrari | GTO | |
| 68 | Mendez / Almeida / Rodriguez | T & R Racing (DR) | | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 69 | Henn / Dieudonné / *Paul | Preston Henn (USA) | | Ferrari | 512 BB | /LM | Ferrari | GTX | |
| 70 | Doyle / Guest / Meyer | Herman Racing (USA) | Chris Doyle | Mazda | RX-7 | | Mazda | GTU | |
| 71 | Keirn / Trotter / Errington | Keirn Garage (USA) | Philip Keirn | Chevrolet | Corvette | C3 | Chevrolet | GTO | |
| 73 | Hutchins / Honegger / Apgar | Z&W Enterprises (USA) | | Mazda | RX-7 | | Mazda | GTU | |
| 75 | Kreider / Hagan / Bond | Show Cars of Florida (USA) | Dale Kreider | Chevrolet | Corvette | C3 | Chevrolet | GTO | |
| 76 | Chamberlain / Chamberlain / Valentine | Arrow Heating Co. (USA) | Richard J. Valentine | Chevrolet | Corvette | C3 | Chevrolet | GTX | |
| 77 | Mandeville / Downing / Frisselle | Roger Mandeville (USA) | Roger Mandeville | Mazda | RX-7 | | Mazda | GTU | |
| 78 | Giesel / Nesbitt / Johnson | Revolution Wheels (USA) | | Mazda | RX-2 | | Mazda | GTU | |
| 79 | Bergstrom / Bedard | Sports Ltd. Racing (USA) | Bob Bergstrom | Mazda | RX-7 | | Mazda | GTU | |
| 80 | Carter / Carter / Edwards | All Canadian Racing (CDN) | | Chevrolet | Camaro | II | Chevrolet | GTX | |
| 81 | St. James / Welch / Winters | Trinity Racing | | Mazda | RX-7 | | Mazda | GTU | |
| 82 | Casey / Dietrich / Mueller | Trinity Racing (USA) | | Mazda | RX-7 | | Mazda | GTU | |
| 83 | Zitza / *Belperche / *Zitza | Zotz Garage (USA) | | Porsche | 914 | /6 | Porsche | GTU | |
| 85 | Deacon / Moennick / Bienvenue | David Deacon (CDN) | | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 88 | *Adams / *Roberts / *Evans | Herb Adams VSE (USA) | Herb Adams | Pontiac | Firebird | Trans-Am | Pontiac | GTO | |
| 89 | Romero / Libert / Soto | Hector Huerta (YV) | | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 91 | Mitt / Valentine / Pearl | Grand Prix International (USA) | Richard J. Valentine | Chevrolet | Corvette | | Chevrolet | GTX | |
| 92 | Cummings / Levetto | The Cummings Marque | Don Cummings | Shelby | GT350 | | Ford | GTO | |
| 93 | Whittington / Whittington / Whittington | Whittington Bros. (USA) | Whittington Brothers | Porsche | 935 | K3 | Porsche | GTX | +2000/Gr.5 |
| 94 | Whittington / Plankenhorn | Whittington Bros. (USA) | Whittington Brothers | Porsche | 935 | /79 | Porsche | GTX | |
| 95 | Ramirez / Villa / Gordillo | Mike Ramirez Racing | Mike Ramirez | Porsche | 911 | | Porsche | GTU | |
| 96 | Earl / Coykendall / Stiff | NTS Racing | | Datsun | 240Z | | Datsun | GTU | |
| 98 | Van Every / Tisdelle / Johnson | Van Every Racing (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO | |
| 99 | Phil Currin | Full-Time Racing (USA) | Kal Showket | Chevrolet | Corvette | | Chevrolet | GTO | |