| 0 | Wonzer / Taylor | Gary Wonzer (USA) | | Chevron | GTP | | Buick | GTP |
| 00 | Kendall / Kendall / Jones | Tommy Kendall (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 01 | Bell / Brockman / Riggins | Charles Young | | Argo | JM16 | | Buick | GTP |
| 02 | Newsome / McVey / Kreider | RNGC Racing | | Mazda | RX-7 | | Mazda | GTU |
| 04 | Redman / Haywood | Group 44 (USA) | | Jaguar | XJR-5 | | Jaguar | GTP |
| 05 | Whitaker / Crosby / McDill / *Hudlett | Robert Whitaker | | Chevrolet | Camaro | | Chevrolet | GTP |
| 08 | Olson / Potter / *Romano | Simms-Romano (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 09 | Uria / Schaefer / Figaro / Refenning | 901 Shop (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 1 | Whittington / Lanier | Blue Thunder Racing Team (USA) | | March | 84G | | Chevrolet | GTP |
| 2 | Leon / Leon / McKitterick | Leon Bros. Racing (USA) | Leon Brothers | March | 85G | | Porsche | GTP |
| 3 | Paul, Jr. / Madren / Pickering | Pegasus Racing (USA) | | March | 84G | | Buick | GTP |
| 4 | Baird / Labonte / *Hagan | Lee Racing | | Chevrolet | Corvette GTP | | Chevrolet | GTP |
| 5 | Stuck / Akin / Mullen | Bob Akin Motor Racing (USA) | | Porsche | 962 | | Porsche | GTP |
| 6 | Morgan / Alsup | Morgan Performance (USA) | | Royale | RP40 | | Buick | GTP |
| 7 | Wollek / Whittington / Henn | Henn's Swap Shop Racing (USA) | Preston Henn | Porsche | 935 | L | Porsche | GTP |
| 8 | Foyt / Wollek | Preston Henn (USA) | Preston Henn | Porsche | 962 | | Porsche | GTP |
| 11 | Kendall / Hotchkis / Kirby | Kendall Racing (USA) | Chuck Kendall | Porsche | 935 | K3/80 | Porsche | GTP |
| 12 | Schwarz / Jelinski / *Thoelke | Gebhardt Motorsports (D) | | Gebhardt | JC853 | | Ford | GTP |
| 13 | Wagoner / Knott / *Rubino | Rubino Racing (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 14 | Holbert / Bell / Unser, Jr. | Holbert Racing (USA) | Al Holbert | Porsche | 962 | | Porsche | GTP |
| 15 | Kalagian / Lloyd / Grunnah | John Kalagian Racing (USA) | John Kalagian | March | 84G | | Chevrolet | GTP |
| 16 | Hinze / Minter / Yarosh | Marty Hinze Racing (USA) | Marty Hinze | Porsche | 935 | K3 | Porsche | GTP |
| 17 | Bacon / Guest / Akin | Al Bacon Racing (USA) | Al Bacon | Mazda | RX-7 | | Mazda | GTU |
| 20 | Silver / Herman / Baker | Spirit of Cleveland | Richard Silver | Porsche | 935 | JLP-2 | Porsche | GTP |
| 21 | Gelles / Cohen / *Walker | Gopher Motion | | Ferrari | 512 BB | /LM | Ferrari | GTO |
| 22 | Taylor / Hayes-Harlow / Albanese | Walter Johnston (USA) | | Pontiac | Firebird | | Pontiac | GTO |
| 23 | Raul Garcia | Superior Racing Team (USA) | Raul Garcia | Pontiac | Firebird | | Pontiac | GTO |
| 25 | Boyer / Roberts / Barben | Steve Roberts | | Chevrolet | Camaro | | Chevrolet | GTO |
| 26 | Frank / White / Kendall | Toyota Village (USA) | Werner Frank | Porsche | 935 | /80 | Porsche | GTP |
| 29 | Brassfield / Luyendyk / Brassfield | DeAtley Racing | | March | 85G | | Chevrolet | GTP |
| 31 | Goral / Wilson | Goral Racing (USA) | Paul Goral | Porsche | 935 | | Porsche | GTP |
| 32 | Bossom / *Hill / *Riley | KJJ Enterprises | | Triumph | TR8 | | Rover | GTO |
| 34 | O'Brien / Van Steenburg | O'Brien - van Steenburg Racing | | Mazda | OVS-1 | | Mazda | Lights |
| 35 | Griffin / Hefner / Winfree | Team Dallas | | Porsche | 911 Carrera | RSR | Porsche | GTU |
| 36 | Case / Panaccione | Case Racing (USA) | | Porsche | 911 | | Porsche | GTU |
| 37 | Burdsall / Welter / Nicholson | Burdsall - Welter Racing | | Tiga | GT284 | | Mazda | Lights |
| 38 | Mandeville / Blackburn | Mandeville Auto Tech (USA) | Roger Mandeville | Mazda | RX-7 | | Mazda | GTO |
| 39 | Brezinka / Centeno / Hochreuter | R & H Racing (CDN) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 42 | Lewis / Pruett / Varde | Mike Meyer/Daffy (USA) | Mike Meyer | Mazda | RX-7 | | Mazda | GTU |
| 43 | DeNarvaez / Cowart / Miller | De Narvaez Enterprises (CO) | Mauricio DeNarvaez | Porsche | 935 | J | Porsche | GTP |
| 44 | Robinson / Tullius | Group 44 (USA) | | Jaguar | XJR-5 | | Jaguar | GTP |
| 45 | Gordillo / Falgueras / Villa | Pennzoil de P. R. | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 47 | Bohren / Millen / *Dingman | Dingman Brothers Racing (USA) | | Pontiac | Firebird | | Pontiac | GTO |
| 48 | Cripe / *Wonzer / *Dewey | Gary Wonzer (USA) | Gary Wonzer | Porsche | 934 | S | Porsche | GTO |
| 49 | Munoz / Lopez / Galeano | Conrad Racing | | Porsche | 911 | | Porsche | GTU |
| 50 | McCall / Carter / *Sheehy | Monty Trainer's Restauarant | | Chevrolet | Camaro | | Chevrolet | GTO |
| 51 | McComb / Mancuso / Fiala | Mosler Racing | | Ferrari | 512 BB | /LM | Ferrari | GTO |
| 53 | Smith / Waugh | Mandeville Auto Tech (USA) | Roger Mandeville | Mazda | RX-7 | | Mazda | GTO |
| 54 | Zwiren / Tearney / Peters | Zwiren Racing | | Mazda | RX-7 | | Mazda | GTU |
| 55 | Heinz / Trueman / Thompson / *Eisenlohr | Dave Heinz Imports (USA) | | Chevrolet | Corvette | | Chevrolet | GTO |
| 56 | Auberlen / Jauker / Gang / Eisenlohr | SP Racing (USA) | | Porsche | 911 Carrera | | Porsche | GTU |
| 58 | Borlase / Hammond / Torres | Coin Operated Racing (USA) | Rick Borlase | Porsche | 934 | | Porsche | GTO |
| 60 | Hunt / Shelton / *Jameson | Tom Hunt | | Mazda | RX-3 | | Mazda | GTU |
| 61 | Courtney / O'Neill / Hackney | Team USA Racing (USA) | | Chevrolet | Monza | | Chevrolet | GTO |
| 63 | Downing / Maffucci | Jim Downing (USA) | | Argo | JM16 | | Mazda | Lights |
| 65 | Dallenbach, Jr. / Jones | Team Roush Protofab (USA) | Jack Roush | Ford | Mustang | | Ford | GTO |
| 66 | Habersin / Habersin | Habersin Camera Shop | | Chevrolet | Camaro | | Chevrolet | GTO |
| 67 | Busby / Morton / Mass | Busby Racing (USA) | Jim Busby | Porsche | 962 | | Porsche | GTP |
| 68 | Halsmer / Knoop / Quester | Busby Racing (USA) | Jim Busby | Porsche | 962 | | Porsche | GTP |
| 69 | Hofstra / Slater / Robinson | Wonzer Racing (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 70 | Cummings / Rubright / *Walker | Ormond Racing Associates | | Chevrolet | Corvette | | Chevrolet | GTO |
| 71 | Johnson / Dunham / *Shaw | Team Highball (USA) | Amos Johnson | Mazda | RX-7 | | Mazda | GTU |
| 74 | Godsey / Gentilozzi / Hill | Whitehall Promotions (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTU |
| 75 | Worth / Gritzalis | Pettit Wholesale | | Mazda | RX-3 | | Mazda | GTU |
| 76 | Baldwin / Kline / *Young | Malibu Grand Prix (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 77 | Munoz / Gonzalez | Tortuga Racing | | Chevrolet | Camaro | | Chevrolet | GTO |
| 78 | Higgins / Mead / King | Tokina Zoom Lenses (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 79 | Forbes-Robinson / Winters / Bergstrom | Whitehall Motorsports (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTU |
| 80 | Catter / Coco | Carlos Catter | | Chevrolet | Camaro | | Chevrolet | GTO |
| 81 | Bupp / Church / Generotti | Ken Bupp (USA) | | Chevrolet | Camaro | | Chevrolet | GTO |
| 83 | Keck / Wessel / Montgomery | K & P Racing (USA) | Karl Keck | Chevrolet | Corvette | C3 | Chevrolet | GTO |
| 85 | Nooe / Stricklin / Stringfellow | Don Nooe | | Chevrolet | Corvette | | Chevrolet | GTO |
| 87 | Alderman / Hill / Alexander | Mosler Racing | | Ferrari | 308 GTB | | Ferrari | GTU |
| 88 | Shafer / Shafer / Maloy | Schaferacing (USA) | Craig Shafer | Chevrolet | Camaro | III | Chevrolet | GTO |
| 89 | "Jamsal" / Fonseca / Mena | Latino Racing (CR) | | Porsche | 934 | | Porsche | GTO |
| 90 | Delano / Petery / Moise | Road Circuit Technology | | Pontiac | Firebird | | Pontiac | GTO |
| 92 | Gennone / Overbagh / *Prego | OMR Engines (USA) | Hoyt Overbagh | Chevrolet | Camaro | III | Chevrolet | GTO |
| 93 | Marsh / Pawley / Marsh | Mid-O/Rusty Jones (USA) | | Argo | JM16 | | Mazda | Lights |
| 95 | Van Every / Tisdelle / *Refenning | Van Every Racing (USA) | Ash Tisdelle | Porsche | 935 | | Porsche | GTP |
| 98 | Lee / Julian / Hudlett | Bob's Speed Products | | Buick | Skyhawk | | Buick | GTO |