| 00 | van der Merwe / Martin | Kreepy Krauly Racing (ZA) | Sarel van der Merwe | March | 83G | | Porsche | GTP |
| 04 | Van / Leven | GP 24 Ltd. | | Porsche | 924 | Carrera GTR | Porsche | GTU |
| 07 | Jim Trueman | Bell Racestar/LSJ Racing (USA) | | Argo | JM16 | | Ford | GTP |
| 08 | Glick / Scyphers | Scyphers-Ankor Racing (USA) | | Ferrari | 308 GTB | | Ferrari | GTO |
| 2 | Leon / Leon / Haywood | Leon Bros. Racing (USA) | Leon Brothers | March | 84G | | Chevrolet | GTP |
| 3 | Madren / Speer / Pickering | Pegasus Racing (USA) | | March | 84G | | Buick | GTP |
| 4 | Hagan / Felton | Stratagraph (USA) | Billy Hagan | Chevrolet | Camaro | III | Chevrolet | GTO |
| 5 | Akin / O'Steen | Bob Akin Motor Racing (USA) | Bob Akin | Porsche | 935 | -84 | Porsche | GTP |
| 6 | | Europa Motors | | BMW | 3.0 CSL | | BMW | GTO |
| 7 | Rahal / Ludwig | Team Zakspeed USA | | Ford | Mustang GTP | | Ford | GTP |
| 9 | Baker / Newsum | Personalized Autohaus (USA) | Wayne Baker | Porsche | 935 | K3 | Porsche | GTP |
| 10 | Vincentz / Mullen / Canepa | Electrodyne | | Lola | T600 | | Chevrolet | GTP |
| 11 | Kendall / Cook | Kendall Racing (USA) | Charles Kendall | Lola | T600 | | Chevrolet | GTP |
| 13 | Rubino / Leira | Rubino Racing (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 15 | Kalagian / Lloyd | Kalagian Ardisana Racing (USA) | John Kalagian | Lola | T600 | | Chevrolet | GTP |
| 18 | "Fomfor" / Naon / Montoya | Fomfor Racing (ES) | "Fomfor" | Sauber | C7 | | BMW | GTP |
| 19 | Hoshino / Sekiya | All-American Racers | | Tom's | 83C | | Toyota | GTP |
| 22 | Taylor / Taylor / Sabino | Walter Johnson (USA) | | Pontiac | Firebird | | Pontiac | GTO |
| 24 | Griffin / Allen / Schwarz | Pegasus Racing (USA) | Martin L. Speer | Porsche | 935 | JLP-2 | Porsche | GTP |
| 25 | Miller / DeNarvaez | Red Lobster Racing (USA) | David Cowart | March | 83G | | Chevrolet | GTP |
| 26 | Nardi / Nardi | Nardi Motors | | Porsche | 911 | | Porsche | GTU |
| 30 | Moretti / Ballabio | Momo Corse (I) | | Alba | AR3 | | Ford | GTP |
| 31 | Marx / Follmer / Amberg | Marx/Lanfre Racing (USA) | Tom Alan Marx | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 33 | Torres / Thomas | BCW Racing (USA) | Jim Torres | Porsche | 935 | K3 | Porsche | GTP |
| 36 | Chasse / Kirby | Maurice Chasse | | Porsche | 914 | /6 | Porsche | GTU |
| 38 | Mandeville / Johnson | Mandeville Auto/Tech (USA) | Roger Mandeville | Mazda | RX-7 | | Mazda | GTO |
| 42 | Lewis / Bloomer / Vegher | Phil Conte (USA) | Phil Conte | Mazda | RX-7 | | Mazda | GTU |
| 43 | Montoya / *Goellnicht | Walker-Brown Racing (USA) | | BMW | M1 | | BMW | GTO |
| 45 | Morton / Adamowicz | Phil Conte (USA) | Phil Conte | Lola | T600 | | Chevrolet | GTP |
| 47 | Bohren / Millen | Dingman Bros. Racing (USA) | Dingman Brothers | Chevrolet | Corvette | C3 | Chevrolet | GTO |
| 48 | Honsowetz / Barnhold / Jones | Datsun Alley Racing | | Datsun | 280ZX | | Datsun | GTO |
| 50 | Ray McIntyre | Racing Systems | | Chevrolet | Corvette | GTP | Chevrolet | GTP |
| 53 | Winthrop / Jackson | Air Group Racing (USA) | | Porsche | 911 | | Porsche | GTU |
| 54 | Jauker / Auberlen | SP Racing (USA) | | Porsche | 911 Carrera | | Porsche | GTO |
| 55 | Hackman / *Ganz | Preston & Son Ent. | | Mazda | RX-7 | | Mazda | GTU |
| 56 | Lanier / Whittington | Blue Thunder Racing (USA) | | March | 84G | | Chevrolet | GTP |
| 57 | Whittington / Lanier | Blue Thunder Racing (USA) | | March | 83G | | Chevrolet | GTP |
| 58 | Borlase / Kravig / Hammond | Coin Operated Racing (USA) | Rick Borlase | Porsche | 934 | | Porsche | GTO |
| 63 | Downing / Maffucci | RGP 500 Racing (USA) | | Argo | JM16 | | Mazda | GTP |
| 66 | Dunham / Kline | Mike Meyer Racing (USA) | Mike Meyer | Mazda | RX-7 | | Mazda | GTU |
| 67 | Busby / Grable / Knoop | B. F. Goodrich (USA) | Jim Busby | Lola | T616 | | Mazda | GTP |
| 70 | Chmura / Regan / Koobation | Larry Chmura (USA) | | Porsche | 911 Carrera | | Porsche | GTO |
| 75 | Schwarz / Christian / Swart | European Auto Restoration (USA) | | Ferrari | 365 GT4/BB | | Ferrari | GTP |
| 76 | Baldwin / Young / Reed | Malibu Grand Prix (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 77 | Bauer / Jenner | Brooks Racing (USA) | | Ford | Thunderbird | | Ford | GTO |
| 79 | Bergstrom / *Winters | Whitehall/Promotion (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTU |
| 80 | Klug / Lindley | John Klug (USA) | John Klug | Porsche | 934 | | Porsche | GTO |
| 82 | Mueller / Visger | Casey/Haggard Racing (USA) | Casey/Haggard | Mazda | RX-7 | | Mazda | GTU |
| 84 | Young / Grunnet | Dole Frech Fruit Racing (USA) | Clay Young | Pontiac | Fiero | | Pontiac | GTU |
| 85 | Blackburn / *Devendorf | Blackburn Racing (USA) | Logan Blackburn | Datsun | 280ZX | | Datsun | GTU |
| 86 | Holbert / Bell | Bayside Disposal Racing (USA) | | Porsche | 962 | | Porsche | GTP |
| 87 | Schneider / Forbes-Robinson | Performance Motorsports (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTU |
| 98 | Aase / Dallenbach, Jr. | All-American Racers (USA) | Dan Gurney | Toyota | Celica | Mk III | Toyota | GTU |
| 99 | Adams / *Cord | All-American Racers (USA) | Dan Gurney | Toyota | Celica | Mk III | Toyota | GTU |