| 0 | Field / Whittington / *Ongais | Interscope Racing (USA) | Ted Field | Lola | T600 | | Chevrolet | GTP |
| 00 | Field / Ongais / Whittington | Interscope Racing (USA) | Ted Field | Lola | T600 | | Chevrolet | GTP |
| 01 | Morton / Klausler / Bucknum | Marketing Corporation (USA) | | Ford | Mustang | | Ford | GTO |
| 02 | Minter / Bucknum | Marketing Corp. of America | | Ford | Mustang | | Ford | GTO |
| 03 | Pallavicini / Frank | Angelo Pallavicini (CH) | | Porsche | 935 | | Porsche | GTP |
| 04 | Canary / Libert / Witmeur / *Carmillet | Paul Canary Racing (USA) | | Pontiac | Firebird | | Pontiac | GTO |
| 05 | Almeida / Morejon / Soto | T & R Racing (USA) | Tico Almeida/Rene Rodriguez | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 06 | Diehl / Newsome | Bobby Diehl | | Mazda | RX-7 | | Mazda | GTO |
| 07 | Heimrath / Heimrath, Jr. | Heimrath Racing (CDN) | Ludwig Heimrath | Porsche | 934 | | Porsche | GTO |
| 09 | Ciccone / *Shinn / *Cogbill, Sr. | Mark Gassaway | | Chevrolet | Camaro | | Chevrolet | GTO |
| 1 | Paul, Jr. / Rodriguez / Castellano | JLP Racing (USA) | John Paul | Porsche | 935 | JLP-3 | Porsche | GTP |
| 2 | Marty Hinze | Hinze Fencing (USA) | Marty Hinze | Porsche | 935 | K3 | Porsche | GTP |
| 4 | Hagan / Labonte / Frink | Stratagraph Inc. (USA) | Billy Hagan | Chevrolet | Camaro | III | Chevrolet | GTO |
| 5 | Akin / O'Steen / *Whittington | Bob Akin Motor Racing (USA) | Bob Akin | Porsche | 935 | K3/80 | Porsche | GTP |
| 6 | Wollek / Ballot-Léna / Henn / Foyt | Henn's Swap Shop Racing (USA) | Preston Henn | Porsche | 935 | L | Porsche | GTP |
| 7 | Halsmer / Reed / Knoop | Racing Beat | | Mazda | RX-7 | | Mazda | GTO |
| 8 | Paul / *Currin | JLP Racing (USA) | John Paul | Porsche | 935 | JLP-4 | Porsche | GTP |
| 9 | Baker / Mullen / Garretson | Personalized Autohaus (USA) | Wayne Baker | Porsche | 934 | | Porsche | GTO |
| 10 | Kent-Cooke / Adams / Bright / *Leung | Cooke Racing (USA) | Ralph Kent-Cooke | Lola | T600 | | Chevrolet | GTP |
| 11 | Foyt / Waltrip / Maldonado / *Needell | Nimrod Racing (GB) | | Nimrod | NRA/C2 | | Aston Martin | GTP |
| 13 | Eitel / Brummer / Pate | Gordon Oftedahl (USA) | Gordon Oftedahl | Pontiac | Firebird | | Pontiac | GTO |
| 14 | Raub / Moses / Shafer | Oftedahl Racing (USA) | | Pontiac | Firebird | | Pontiac | GTO |
| 15 | Lutz / Panaccione / Connor / Prego | D & L Performance (USA) | | Porsche | 911 Carrera | RSR 3.0 | Porsche | GTO |
| 16 | Goral / Figaro / Northam | Paul Goral (USA) | Paul Goral | Porsche | 911 | | Porsche | GTU |
| 17 | Dingman / Bighouse / Gunn | Dingman Brothers Racing (USA) | Dingman Brothers | Chevrolet | Corvette | | Chevrolet | GTO |
| 18 | Collins / Nelson / Vosta | Bill Nelson | | Pontiac | Firebird | | Pontiac | GTO |
| 19 | Van Every / *Tisdelle | Van Every Racing (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 20 | Kreider / Heinz | Dale Kreider (USA) | Dale Kreider | Chevrolet | Corvette | | Chevrolet | GTO |
| 21 | St. James / Graham / Olson | Nimrod Racing (GB) | | Nimrod | NRA/C2 | | Aston Martin | GTP |
| 23 | Garcia / DiLella / Fernandez | Superior Racing Team (USA) | Raul Garcia | Chevrolet | Camaro | II | Chevrolet | GTO |
| 24 | Speer / Madren / Ratcliff | Pegasus III Racing (USA) | Martin L. Speer | Porsche | 935 | JLP-2 | Porsche | GTP |
| 25 | Cowart / Miller / *DeNarvaez | Red Lobster Racing (USA) | David Cowart | March | 82G | | Porsche | GTP |
| 26 | Nehl / Silcox / Valentine | Auriga Racing (USA) | | Chevrolet | Camaro | III | Chevrolet | GTO |
| 27 | Fowells / Mummery / Sheehy | Scuderia Rosso (USA) | Jim Fowells | Mazda | RX-7 | | Mazda | GTU |
| 28 | Adams / Martin / Ruttman / Emanuelson / *Meldeau | Avanti | | Avanti | II | | | GTO |
| 29 | Overby / Doyle / Bell | Overby's | | Chevrolet | Camaro | | Chevrolet | GTO |
| 30 | Rynerson / Case | Case Racing | | Porsche | 911 | | Porsche | GTU |
| 31 | Kreider / Neland / *Kuhel | Kendco | | Chevrolet | Camaro | | Chevrolet | GTO |
| 32 | Cline / Romano / Powell | Richard Cline | Richard Cline | Mazda | RX-7 | | Mazda | GTU |
| 35 | Gilgan / Leon / Pickering | Pegasus Racing | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 36 | Miller / Busby / Grable | Herman & Miller P & A (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTO |
| 37 | Burdsall / Welter / Bacon | Burdsall-Welter Racing | | Mazda | RX-7 | | Mazda | GTU |
| 38 | Mandeville / Johnson / Smith | Mandeville Auto/Tech (USA) | Roger Mandeville | Mazda | RX-7 | | Mazda | GTU |
| 39 | Flores / Gottfried / Holmes | Donald Flores (USA) | | Porsche | 911 | | Porsche | GTU |
| 40 | Bieri / Gysler / Hubbard | Bieri Racing (CDN) | | BMW | M1 | | BMW | GTO |
| 41 | Schmidt / Schmidt | Starved Rock Lodge | | Chevrolet | Corvette | | Chevrolet | GTO |
| 42 | Bean / Cason / Wonzer | Gary Wonzer (USA) | Gary Wonzer | Porsche | 911 | S | Porsche | GTU |
| 43 | Richardson / Young / *Gregg | Bob Gregg Racing (USA) | Bob Gregg | Chevrolet | Camaro | | Chevrolet | GTO |
| 44 | Tullius / Adam / Bedard | Group 44 (USA) | | Jaguar | XJR-5 | | Jaguar | GTP |
| 45 | Felton / Williams / Frink | Stratagraph Inc. (USA) | Billy Hagan | Chevrolet | Camaro | | Chevrolet | GTO |
| 47 | Rubino / Romero / Bundy / Whittington | Frank Rubino (USA) | Pepe Romero | Porsche | 935 | M16 | Porsche | GTP |
| 49 | Overbagh / Kirill / Price | OMR Engines (USA) | | Chevrolet | Monza | | Chevrolet | GTO |
| 50 | Febles / Fonseca / Valverde | Latino Racing (CR) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 51 | Carmean / Herman / Finger | Red Roof Inns (USA) | Jim Trueman | Mazda | RX-7 | | Mazda | GTU |
| 52 | Cripe / Gauthier / Duncan / Swanson | TFC Racing | | Porsche | 911 | | Porsche | GTU |
| 55 | Montoya / Herman / Garcia | B de T Racing | | BMW | M1 | | BMW | GTO |
| 58 | Rude / Gregg / Henn | Brumos Racing (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTO |
| 60 | Dietrich / Ivey / Cook | Team Morrison | Tommy Morrison | Mazda | RX-7 | | Mazda | GTU |
| 61 | O'Neill / Courtney / Sereix | Vista Racing (USA) | | Chevrolet | Monza | | Chevrolet | GTO |
| 63 | Downing / Maffucci / Potter | RGP 500 Racing (USA) | Jim Downing | Mazda | RX-7 | | Mazda | GTU |
| 64 | Hulen / Coupland / Speakman | John Hulen (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 65 | Baird / Mead / Pumpelly | Prancing Horse Fram Racing | Ron Spangler | Ferrari | 512 BB | /LM | Ferrari | GTP |
| 66 | Dunham / Kline / Compton | Mike Meyer Racing (USA) | Mike Meyer | Mazda | RX-7 | | Mazda | GTU |
| 67 | Forbes-Robinson / Witzenburg / Swan / *Petty | Trans Am Specialtes | | Pontiac | Firebird | | Pontiac | GTO |
| 69 | Londono / Londono / Flaquer | Conrado Casado | | Porsche | 911 | | Porsche | GTU |
| 71 | Morgan / Johnson / Miller | Morgan Performance Group (USA) | Charles Morgan | Datsun | 280ZX | | Datsun | GTU |
| 72 | Baker / Marlin | John Josey | | Chevrolet | Corvette | | Chevrolet | GTO |
| 73 | Grostic / Lawhorn | G. O. Racing | | Porsche | 914 | /4 | VW | GTU |
| 74 | Taylor / Angus / Dassinger | Mark Wagoner (USA) | | Chevron | GTP | | Buick | GTP |
| 75 | Boand / Anderson / Stephens | Bard Boand (USA) | | Chevrolet | Corvette | | Chevrolet | GTO |
| 77 | Bohren / Honegger / Palmer | Z & W Enterprises (USA) | | Mazda | GTP | | Mazda | GTP |
| 78 | Bitterauf / Smith / Flanders | Der Klaus Haus | | Porsche | 911 | | Porsche | GTU |
| 79 | Winters / Bergstrom / Dawe | Whitehall Promotions (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTO |
| 81 | Whitaker / McDill / Keck | Robert Whitaker (USA) | | Chevrolet | Camaro | | Chevrolet | GTO |
| 82 | Varde / Casey / *Baldwin | Trinity Racing (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 83 | Gassaway / Smith, Sr. / Cogbill, Sr. / Cogbill | Thomas T. Ciccone | | Chevrolet | Camaro | | Chevrolet | GTP |
| 84 | Donaldson / Pope / Murray | Motorsport Marketing | Ken Murray | Chevrolet | Camaro | | Chevrolet | GTO |
| 85 | Lloyd / Drolsom / Palmer | Richard Lloyd (GB) | | Porsche | 924 | Carrera GTR | Porsche | GTO |
| 86 | Haywood / Leven / Holbert | Bayside Disposal Racing (USA) | Bruce Leven | Porsche | 935 | /80 | Porsche | GTP |
| 87 | Beasley / Ashford / *Lewis | Bob Beasley (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 88 | Wolters / Lanier / Hinze / *Murray | Motorsports Marketing (USA) | Ken Murray | March | 83G | | Chevrolet | GTP |
| 89 | "Jamsal" / Galdamez / Barrientos | Taca El Salvador (ES) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 90 | Schaefer / Refenning / Belperche / Zitza | 901 Shop (USA) | | Porsche | 911 | SC | Porsche | GTU |
| 92 | Mueller / McDonough / Visger | Kent Racing (USA) | David Kent | Mazda | RX-7 | | Mazda | GTU |
| 97 | Dallenbach, Jr. / Ribbs / Ganz | All American Racers (USA) | Dan Gurney | Toyota | Celica | Mk III | Toyota | GTU |
| 98 | Aase / Unser, Jr. / Chandler | All American Racers (USA) | Dan Gurney | Toyota | Celica | Mk III | Toyota | GTU |
| 99 | Hackman / Sekiya / Hoshino | All American Racers (USA) | Dan Gurney | Toyota | Celica | Mk III | Toyota | GTU |