| 0 | van der Merwe / "Winter" / Ongais | Joest Racing (D) | Reinhold Joest | Porsche | 962 | | Porsche | GTP |
| 00 | Slater / Duttinger / Bartling | S Squared Engineering | | Porsche | 911 Carrera | RSR | Porsche | GTU |
| 01 | Kline / Bell | Spice Engineering | | Spice | SE86CL | | Pontiac | Lights |
| 04 | Pilla / *White / *Drolsom | Dave White Racing | | Porsche | 944 | Turbo | Porsche | GTO |
| 05 | Morgan / Rothbarth | RM Racing | | Royale | RP40 | | Mazda | Lights |
| 06 | Cross / Smith / Lee | Art Cross | | Chevrolet | Monte Carlo | | Chevrolet | GTO |
| 08 | Romano / Swifts / Drew | Simms Romano Enterprise (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 09 | Durst / Brockman / Belcher | Ball Bros. Racing | | Spice | SE86CL | | Pontiac | Lights |
| 1 | Foyt / Sullivan / Haywood | A J Foyt Enterprises (USA) | | Porsche | 962 | | Porsche | GTP |
| 3 | Gimondo / Grostic / Wolters | Vince Gimondo | | Oldsmobile | Calais | | Oldsmobile | GTO |
| 4 | Pruett / Halsmer | Roush Racing (USA) | | Ford | Mustang GTX Special | | Ford | GTP |
| 5 | Weaver / Akin / Shelton | Bob Akin Motor Racing (USA) | | Porsche | 962 | | Porsche | GTP |
| 8 | Redman / Kneifel / Forbes-Robinson | Primus Motorsport | | Porsche | 962 | | Porsche | GTP |
| 9 | Tomlinson / Loebel / Morgan | Finco Racing | | Tiga | GT285 | | Mazda | Lights |
| 10 | Stricklin / Nooe / Stringfellow | Don Nooe | | Chevrolet | Corvette | | Chevrolet | GTO |
| 11 | St. James / Gloy / *Akin | Roush Racing (USA) | Jack Roush | Ford | Mustang | | Ford | GTO |
| 12 | Shafer / Nehl / Peters | Centurion AutoTransport | | Buick | Somerset | | Buick | GTO |
| 13 | Altman / Altman / Selby | Altman Bros Motor Racing (USA) | | Porsche | 914 | /6 | Porsche | GTU |
| 14 | Robinson / Holbert | Holbert Racing (USA) | Al Holbert | Porsche | 962 | | Porsche | GTP |
| 15 | Murray / Visger | Murray Racing (USA) | Dick Murray | Pontiac | Fiero | | Pontiac | GTU |
| 16 | Cobb / Schuppan / *Dyson | Dyson Racing (USA) | Rob Dyson | Porsche | 962 | | Porsche | GTP |
| 17 | Bacon / Reed | Al Bacon Racing (USA) | Al Bacon | Mazda | RX-7 | | Mazda | GTU |
| 18 | Evans / Pilgrim / Goad / McKenna | Jeff Bietzel | | PAS | | | Pontiac | Lights |
| 19 | Schubot / Ludemann / Jones | S & L Racing (USA) | | Tiga | GT285 | | Mazda | Lights |
| 21 | Felton / *Perkinson / *Mnich | OMR Engines | | Chevrolet | Camaro | | Chevrolet | GTO |
| 22 | Jenner / Akin | Roush Racing (USA) | Jack Roush | Ford | Mustang | | Ford | GTO |
| 23 | Petrilak / Rosenberg / MacInnes | Motion Promotions | | Argo | JM16 | | Buick | Lights |
| 24 | Rubright / Jenkins / Newsome | C A R Enterprises | | Chevrolet | Corvette | | Chevrolet | GTO |
| 25 | Loring / Andrey / Lewis | Gaston Andrey Racing (USA) | Gaston Andrey | Tiga | GT286 | | Ferrari | Lights |
| 26 | Taylor / Montgomery / *Fuller | Bob's Speed Products | | Pontiac | Firebird | | Pontiac | GTO |
| 28 | Pickett / Riggins | Protofab Racing (USA) | | Chevrolet | Camaro | III | Chevrolet | GTO |
| 29 | Phillips / *Canizares / *Katz | Ares Sports | | Tiga | GT286 | | Buick | Lights |
| 30 | McCall / Bohren / Dallenbach | Skoal Bandit Racing | | Chevrolet | Camaro | III | Chevrolet | GTO |
| 31 | Hobbs / Robinson / Hobbs / *Gebhardt | Gebhardt Racing USA | | Gebhardt | JC853 | | BMW | Lights |
| 35 | Gonzalez / Villa / Gordillo | Diman Racing | | Royale | RP40 | | Porsche | Lights |
| 36 | Jellinek / Grooms / *Bagley | Erie Scientific Racing | | Royale | RP40 | | Mazda | Lights |
| 38 | Mandeville / Marsh / *Marsh | Mandeville Auto Tech (USA) | Roger Mandeville | Mazda | RX-7 | | Mazda | GTO |
| 39 | Del Vecchio / Thompson / Mathewson | Gary English | | Chevrolet | Camaro | | Chevrolet | GTO |
| 40 | Bieri / Pallavicini / *Murry | Bieri Racing (CDN) | | Alba | AR2 | | Ferrari | Lights |
| 41 | Graham / Burr / Bryant | B&G Racing | | BMW | 325i | | BMW | GTU |
| 42 | Higgins / Monk / Cherry | MMG/White Allen | | Fabcar | CL | | Porsche | Lights |
| 43 | McAdam / Overbey / Mead | MMG/White Allen | | Fabcar | CL | | Porsche | Lights |
| 44 | Goral / Bond / Figaro | Goral Racing (USA) | Paul Goral | Porsche | 911 | | Porsche | GTU |
| 45 | Pedrera / Dobkin | Carlos Pedrera | | Mazda | RX-7 | | Mazda | GTU |
| 46 | Morejon / Galeano | Turbo Concepts | | Porsche | 911 | | Porsche | GTU |
| 47 | Mills / Oakley | Cumberland Valley Racing (USA) | Chaunce Wallace | Mazda | RX-7 | | Mazda | GTU |
| 48 | Wonzer / Case / Cameron / Cripe | Gary Wonzer Racing (USA) | Gary Wonzer | Porsche | 911 | S | Porsche | GTU |
| 49 | Munoz / Catter / Gonzalez | Catters Racing Team | | Pontiac | Firebird | | Pontiac | GTO |
| 50 | Brosnaham / Cross / Johnson / *Hayes-Harlow | Henry A Brosnaham | | Chevrolet | Camaro | | Chevrolet | GTO |
| 51 | Heinz / Young | Quality Motorsports (USA) | | Chevrolet | Corvette | | Chevrolet | GTO |
| 52 | Case / Dewey / Cason / Northam | Wonzer Racing (USA) | Gary Wonzer | Lola | T616 | | Mazda | Lights |
| 54 | Auberlen / Auberlen / Durkheimer | SP Racing (USA) | | Porsche | 911 Carrera | | Porsche | GTU |
| 56 | Wink / Martin / Erickson / Evans | Bill Wink Racing (USA) | Bill Wink | Chevrolet | Camaro | III | Chevrolet | GTO |
| 60 | DePoyster / Schader / Kurz / Jocelyn | Schaderacing | | Mazda | RX-7 | | Mazda | GTU |
| 61 | O'Neill / Lloyd | Performance Technology (USA) | Brent O'Neill | Argo | JM19 | | Buick | Lights |
| 63 | Downing / Maffucci / O'Steen | Jim Downing (USA) | | Argo | JM19 | | Mazda | Lights |
| 65 | Clinton / Clement / Barrett | Grey Eagle Racing (USA) | Jerry Clinton | Ford | Mustang | | Ford | GTO |
| 67 | Wollek / Brassfield / Dallenbach, Jr. | Busby Racing (USA) | Jim Busby | Porsche | 962 | | Porsche | GTP |
| 68 | Chambers / Wallace / *Meyer | Chambers Racing (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 69 | Kenneth LaGrow | Tom Clark | | Ford | Mustang | | Ford | GTO |
| 70 | Juckette / McDill / *McDill | Hi-Tech Coating | | Chevrolet | Camaro | | Chevrolet | GTO |
| 71 | Johnson / Shaw | Team Highball (USA) | Amos Johnson | Mazda | RX-7 | | Mazda | GTU |
| 72 | Loving / Small / *Goodman | Sunrise Racing | | Chevrolet | Camaro | | Chevrolet | GTO |
| 74 | Gentilozzi / Hoerr / Winters | Whitehall Rocketsports (USA) | Paul Gentilozzi | Oldsmobile | Toronado | | Oldsmobile | GTO |
| 75 | Kendall / Kendall / Jones | Clayton Cunningham Racing (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 76 | Baldwin / Wietzes | Peerless/Hendrick (USA) | | Chevrolet | Camaro | | Chevrolet | GTO |
| 77 | Lappalainen / *Miller | Brooks Racing | | Chevrolet | Camaro | | Chevrolet | GTO |
| 78 | Bartling / Hochreuter / Frank | Fritz Hochreuter (CDN) | | Porsche | 911 | SC | Porsche | GTU |
| 79 | McKitterick / Boady / Lewis | Whitehall Rocketsports | | Alba | AR5 | | Oldsmobile | Lights |
| 80 | Finotto / Melgrati / Silva / *Facetti | Gaston Andrey Racing | | Alba | AR6 | | Ferrari | Lights |
| 81 | Bupp / Church / Taylor | Sentry Bank Equipment (USA) | | Chevrolet | Camaro | | Chevrolet | GTO |
| 82 | Greer / Mees / Finger | Dick Greer Racing (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 83 | Shafer / Maloy / Shafer | Shafer Racing (USA) | Craig Shafer | Chevrolet | Camaro | III | Chevrolet | GTO |
| 84 | Church / Hunt / Generotti | Guy Church (USA) | Guy W. Church | Mazda | RX-7 | | Mazda | GTU |
| 85 | Boyer / Roberts | Highlands Racing | | Pontiac | Firebird | | Pontiac | GTO |
| 86 | Mass / Rahal | Bayside Disposal Racing (USA) | | Porsche | 962 | | Porsche | GTP |
| 86T | | Bayside Disposal Racing (USA) | | Porsche | 962 | | Porsche | GTP |
| 87 | Morrison / Hayner / Knowles / McConnell | Morrison-Cook Motorsport | | Chevrolet | Corvette | | Chevrolet | GTO |
| 88 | Heinricy / *McConnell / *Carradine | Morrison-Cook Motorsport | | Chevrolet | Corvette | | Chevrolet | GTO |
| 89 | Uria / Figaro / Rathbun / Refenning | 901 Racing (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTU |
| 90 | Lee / Myers / Lee | Bob's Speed Products | | Buick | Skyhawk | | Buick | GTO |
| 91 | Gaylord / Albiza / *Stover | Lucas Truck Service | | Oldsmobile | Calais | | Oldsmobile | GTO |
| 92 | Tisdelle / Van Every | Lance Van Every (USA) | | Chevrolet | Camaro | | Chevrolet | GTO |
| 96 | Dibos / Rinzler / *Hessert | Hessert Racing (USA) | | Tiga | GT286 | | Mazda | Lights |
| 98 | Cord / Fangio II | All-American Racers (USA) | Dan Gurney | Toyota | Celica | Turbo | Toyota | GTO |
| 99 | Ribbs / Rice | All-American Racers (USA) | Dan Gurney | Toyota | Celica | Mk IV Turbo | Toyota | GTO |