| 00 | Slater / Senator / Duttinger | S Squared Engineering | | Porsche | 911 Carrera | RSR | Porsche | GTU |
| 01 | Earl / Bell / Kline | Spice Engineering/AT&T | | Spice | SE86CL | | Pontiac | Lights |
| 08 | Swifts / Drew / Hall / Romano | Simms Romano (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 09 | Uria / Figaro / Hayes-Harlow / Rathbun | 901 Racing (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTU |
| 1 | Foyt / Unser / Sullivan | A J Foyt Enterprises (USA) | | Porsche | 962 | | Porsche | GTP |
| 3 | Larrauri / Brancatelli / Sigala | Brun Motorsports (CH) | | Porsche | 962 | | Porsche | GTP |
| 4 | Pruett / Halsmer / Gloy | Roush Racing (USA) | | Ford | Mustang Maxum GTP | | Ford | GTP |
| 5 | Weaver / Stuck / Akin | Bob Akin Motoracing (USA) | | Porsche | 962 | | Porsche | GTP |
| 6 | Dallenbach, Jr. / Jones / Riggins | Protofab Racing (USA) | | Chevrolet | Camaro | III | Chevrolet | GTO |
| 7 | Ganz / Hobbs / Moretti | Zakspeed USA (D) | | Ford | Mustang Probe | | Ford | GTP |
| 8 | Redman / Kneifel / Forbes-Robinson / *Nierop | Primus Motorsport | | Porsche | 962 | | Porsche | GTP |
| 9 | Phillips / Katz / Nelson | Essex Racing | | Tiga | GT285 | | Mazda | Lights |
| 10 | Hotchkis / Adams / Hotchkis, Jr. | Hotchkis Racing (USA) | John Hotchkis | Porsche | 962 | | Porsche | GTP |
| 11 | Gloy / Elliot / St. James / Pruett | Roush Racing (USA) | Jack Roush | Ford | Mustang | | Ford | GTO |
| 13 | Lawhorn / Gimondo / Grostic | Go Racing | | Oldsmobile | Calais | | Oldsmobile | GTO |
| 14 | Robinson / Bell / Unser, Jr. / Holbert | Holbert Racing (USA) | Al Holbert | Porsche | 962 | | Porsche | GTP |
| 16 | Cobb / Dyson / Schuppan | Dyson Racing (USA) | | Porsche | 962 | | Porsche | GTP |
| 17 | Bacon / Millen / Reed | Al Bacon Racing (USA) | Al Bacon | Mazda | RX-7 | | Mazda | GTU |
| 19 | Brown / Schubot / Ludemann | Scott Schubot (USA) | | Tiga | GT285 | | Mazda | Lights |
| 20 | Juckette / McDill / Laws / *McDill | Hi-Tech Coating | | Chevrolet | Camaro | | Chevrolet | GTO |
| 21 | Peters / Nehl / Painter | Western Chemical | | Chevrolet | Camaro | | Chevrolet | GTO |
| 22 | Gregg / Akin / Pruett / Goodyear | Roush Racing (USA) | Jack Roush | Ford | Mustang | | Ford | GTO |
| 23 | Petrilak / Duxbury / Jacobson / *Silberberger | Motion Promotions | | Argo | JM16 | | Buick | Lights |
| 24 | Rubright / Jenkins / Newsome | C A R Enterprises | | Chevrolet | Corvette | | Chevrolet | GTO |
| 25 | Brassfield / Roe / Bauer / Gaston | DeAtley Motorsports | | March | 85G | | Chevrolet | GTP |
| 26 | Bupp / Church / Taylor | Bob's Speed Products | | Pontiac | Firebird | | Pontiac | GTO |
| 27 | Cowart / Miller / Fowells / *Meyer | MSB Racing (USA) | | Argo | JM19 | | Mazda | Lights |
| 28 | Pickett / Waltrip / Labonte | Protofab Racing (USA) | | Chevrolet | Camaro | III | Chevrolet | GTO |
| 29 | Felton / Kimbrough / Overbagh / Perkinson | OMR Engines (USA) | Hoyt Overbagh | Chevrolet | Camaro | III | Chevrolet | GTO |
| 30 | McCall / Bohren / Dallenbach | Skoal Bandit | | Chevrolet | Camaro | III | Chevrolet | GTO |
| 31 | Dickens / Jelinski / Robinson / Hobbs | Gebhardt Racing USA | | Gebhardt | JC853 | | BMW | Lights |
| 32 | Kennedy / Keck / Montgomery / Fuller | K & P Racing (USA) | Karl Keck | Chevrolet | Corvette | C3 | Chevrolet | GTO |
| 33 | Jenner / Morici / Baker | Roush Racing (USA) | Jack Roush | Ford | Mustang | | Ford | GTO |
| 36 | Grooms / Bagley / Jellinek / Pabst | Erie Scientific Racing | | Badger | BB | | Mazda | Lights |
| 38 | Mandeville / Marsh / Smith | Mandeville Auto Tech (USA) | Roger Mandeville | Mazda | RX-7 | | Mazda | GTO |
| 41 | Gralia / Dobkin / *Padrera / *Tagliero | Hugo Gralia | | Mazda | RX-7 | | Mazda | GTU |
| 42 | Cherry / Higgins / King / Mead | White Allen Porsche | | Fabcar | CL | | Porsche | Lights |
| 43 | Pumpelly / Overbey / *McAdam / *Schwietz | White Allen Porsche | | Fabcar | CL | | Porsche | Lights |
| 44 | Tullius / Haywood / Morton | Group 44 (USA) | | Jaguar | XJR-7 | | Jaguar | GTP |
| 47 | Oakley / Wallace / Mills / *Burdsall | Chaunce Wallace Racing (USA) | Chaunce Wallace | Mazda | RX-7 | | Mazda | GTU |
| 50 | Canary / Winston / Currin / *Bryan / *Bryan | Paul Canary Racing (USA) | | Chevrolet | Corvette | | Chevrolet | GTO |
| 51 | Los / Schneider / Andrews | Cosmik-Roy Baker Racing (GB) | Roy Baker | Tiga | GC286 | | Ford | GTP |
| 52 | van der Merwe / Bundy | Hendrick Motorsports (USA) | | Chevrolet | Corvette GTP | | Chevrolet | GTP |
| 54 | Auberlen / Durkheimer / Oest / *Auberlen | SP Racing (USA) | | Porsche | 911 Carrera | | Porsche | GTU |
| 55 | Northam / Lagasse / Krueger / *Walker | Greg Walker Racing | | Chevrolet | Corvette | | Chevrolet | GTO |
| 63 | Downing / O'Steen / Maffucci | Certified Brakes Racing (USA) | | Argo | JM19 | | Mazda | Lights |
| 64 | Johnson / Hassey / Hester | Raintree Corporation | | Ford | Mustang | | Ford | GTO |
| 66 | Morgan / Gennone / Rothbarth / *Meyer | R M Racing | | Royale | RP40 | | Mazda | Lights |
| 67 | Wollek / Busby / Brassfield | Uniroyal Goodrich (USA) | Jim Busby | Porsche | 962 | | Porsche | GTP |
| 68 | DePoyster / Jocelyn / Kurz / Schader | Schaderacing | | Mazda | RX-7 | | Mazda | GTU |
| 71 | Johnson / Shaw / Lazier | Team Highball (USA) | Amos Johnson | Mazda | RX-7 | | Mazda | GTU |
| 74 | Gentilozzi / *Hoerr / *Boody | Whitehall Rocketsports (USA) | Paul Gentilozzi | Oldsmobile | Toronado | | Oldsmobile | GTO |
| 75 | Jones / Kendall / Kendall | CCR (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 76 | Baldwin / Wietzes / *Lloyd | Peerless/Hendrick | | Chevrolet | Camaro | | Chevrolet | GTO |
| 77 | Archer / Archer / *Lappalainen / *Franchi | Brooks Racing | | Chevrolet | Camaro | | Chevrolet | GTO |
| 78 | Chambers / Meyer / Burdsall | Chambers Racing (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 79 | Lewis / *McKitterick / *Winters | Whitehall Rocketsports | | Alba | AR5 | | Oldsmobile | Lights |
| 80 | Andrey / Pallavicini / Bieri | Gaston Andrey Racing | | Alba | AR2 | | Ferrari | Lights |
| 82 | Mees / Greer / Finger | Aspen Inn (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 83 | Gaffney / Reisman / Stone / Hebert | Sasco Motorsports | | Pontiac | Firebird | | Pontiac | GTO |
| 86 | Ludwig / Mass | Bayside Disposal Racing (USA) | | Porsche | 962 | | Porsche | GTP |
| 87 | Morrison / Ceppos / Knowles / Hayner | Morrison-Cook Motorsport | | Chevrolet | Corvette | | Chevrolet | GTO |
| 88 | Heinricy / McConnell / Adam / *Carradine | Morrison-Cook Motorsport | | Chevrolet | Corvette | | Chevrolet | GTO |
| 89 | Durst / Brockman / Belcher / Abel | Ball Brothers Racing (USA) | | Spice | SE86CL | | Pontiac | Lights |
| 90 | Petery / Delano / Carter | Road Circuit Tech | | Buick | Somerset | | Buick | GTO |
| 92 | Van Every / Bond / Tisdelle | Van Every Racing (USA) | | Chevrolet | Camaro | | Chevrolet | GTO |
| 96 | Hessert / Rinzler / Dibos | Hessert Racing | | Tiga | GT286 | | Mazda | Lights |
| 98 | Cord / Millen | All American Racers (USA) | | Toyota | Celica Turbo | | Toyota | GTO |
| 99 | Rudd / Rice / Fangio II | All American Racers (USA) | | Toyota | Celica Turbo | | Toyota | GTO |
| T | | Group 44 (USA) | | Jaguar | XJR-7 | | Jaguar | GTP |