| 0 | van der Merwe / Martin / Scheckter | Kreepy Krauly Racing (ZA) | | March | 84G | | Porsche | GTP |
| 00 | Logan / McRae / Yanke / Phillips | Jim Logan (USA) | | Dodge | Daytona | | Dodge | GTU |
| 02 | Newsome / Kreider | RNGC Racing | | Mazda | RX-7 | | Mazda | GTU |
| 04 | Ballot-Léna / Adams / Robinson | Group 44 (USA) | | Jaguar | XJR-5 | | Jaguar | GTP |
| 05 | Almeida / Morejon | Hi-Tech Racing (USA) | Bill McDill | Porsche | 935 | M16 | Porsche | GTP |
| 06 | Bauer / Miller / Ribbs / *Jones | Team Roush Protofab (USA) | Jack Roush | Ford | Mustang | | Ford | GTO |
| 07 | St. James / Coconis / Lang | LSJ Racing (USA) | | Argo | JM16 | | Ford | GTP |
| 08 | Olson / Potter / Howe / *Romano | Paul Romano (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 09 | Schaefer / Uria / Refenning / Figaro / *Tilton | 901 Shop (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 1 | Whittington / Lanier / Leon | Leon Brothers Racing (USA) | | March | 85G | | Porsche | GTP |
| 2 | McKitterick / Wolters / Leon | Leon Bros Racing (USA) | Leon Brothers | March | 84G | | Chevrolet | GTP |
| 3 | Allison / Pickering / Madren | Pegasus Racing (USA) | | March | 84G | | Buick | GTP |
| 4 | Price / Baird / Hagan / Labonte | Lee Racing | | Lola | T711 | | Chevrolet | GTP |
| 5 | Stuck / Akin / Miller | Bob Akin Motor Racing (USA) | | Porsche | 962 | | Porsche | GTP |
| 6 | Morgan / Alsup / Miller | Morgan Performance (USA) | | Royale | RP40 | | Buick | GTP |
| 7 | Mullen / Nierop / McIntyre | Bob Akin Motor Racing (USA) | Bob Akin | Porsche | 935 | -84 | Porsche | GTP |
| 8 | Foyt / Wollek / Unser / Boutsen / *Howe | Henn's Swap Shop Racing (USA) | Preston Henn | Porsche | 962 | | Porsche | GTP |
| 9 | Newsum / Baker / Mead / Tilton | Personalized Autohaus (USA) | Wayne Baker | Porsche | 935 | K3 | Porsche | GTP |
| 11 | Kendall / Fitzgerald / Hotchkis | Kendall Racing (USA) | Chuck Kendall | Porsche | 935 | K3/80 | Porsche | GTP |
| 13 | Rubino / Wagoner / Knott | Rubino Racing (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 14 | Holbert / Unser, Jr. / Bell | Holbert Racing (USA) | Al Holbert | Porsche | 962 | | Porsche | GTP |
| 15 | Kalagian / Lloyd / Grunnah | Kalagian Racing (USA) | John Kalagian | March | 84G | | Chevrolet | GTP |
| 16 | Grohs / *Schlesser / *Brun / *Henn | Henn's Swap Shop Racing (USA) | Preston Henn | Porsche | 935 | L | Porsche | GTP |
| 17 | Bacon / Guest / Millen | Al Bacon Racing (USA) | Al Bacon | Mazda | RX-7 | | Mazda | GTU |
| 19 | Miller / Ramirez / Redding | Performance Motorcar (USA) | Jack Miller | Nimrod | NRA/C2 | | Aston Martin | GTP |
| 20 | Baker / Herman / Maher / *Silver | Spirit of Cleveland | Richard Silver | Porsche | 935 | JLP-2 | Porsche | GTP |
| 21 | Cohen / Walker / Gelles | Gopher Motion | Don Walker | Ferrari | 512 BB | /LM | Ferrari | GTO |
| 22 | Taylor / Hayes-Harlow / Lee / *Taylor | Walter Johnston (USA) | | Pontiac | Firebird | | Pontiac | GTO |
| 23 | Howes / Reisman / Hebert | Import Restoration | Peter Magnuson | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 24 | Kreider / Newsome | Kreider Racing | Dale Kreider | Chevrolet | Camaro | | Chevrolet | GTO |
| 25 | Miller / Cowart / DeNarvaez | Red Lobster Racing (USA) | David Cowart | March | 83G | | Chevrolet | GTP |
| 27 | Gossett / Stephens / Wolfe | Paul Fortner | | Datsun | 280Z | | Datsun | GTU |
| 28 | Baker / McCall / Ruttman | Southern Racing Promo | John Josey | Chevrolet | Corvette | | Chevrolet | GTO |
| 29 | Roe / Byrne / Brassfield | DeAtley Motorsports | | March | 84G | | Chevrolet | GTP |
| 30 | Moretti / Trueman / Sigala | Momo Corse (I) | | Alba | AR5 | | Ford | GTP |
| 31 | Gralia / Donaldson / Goral | Goral Racing (USA) | Paul Goral | Porsche | 935 | | Porsche | GTP |
| 33 | Anderson / Boand / Brummer | Bo-And Racing | Bard Boand | Lola | T600 | | Chevrolet | GTP |
| 34 | Mena / Drolsom | El Salvador Racing (ES) | George Drolsom | Porsche | 924 | Carrera GTR | Porsche | GTU |
| 35 | Speer / Hefner / Griffin | Team Dallas | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 37 | Welter / Nicholson / Burdsall | Aerex Manufacturing | | Tiga | GT284 | | Mazda | Lights |
| 38 | Yorino / Blackburn / Mandeville | Mandeville Auto-Tech (USA) | Roger Mandeville | Mazda | RX-7 | | Mazda | GTO |
| 41 | Sereix / Noseda | Unlimited Telephones | | Pontiac | Firebird | | Pontiac | GTO |
| 42 | Pruett / Lewis / Varde / *Ware | Mike Meyer/Daffy SWR (USA) | Mike Meyer | Mazda | RX-7 | | Mazda | GTU |
| 43 | Schmidt / Schmidt / Schmidt / *Arkins | Starved Rock Lodge | | Chevrolet | Corvette | | Chevrolet | GTO |
| 44 | Redman / Tullius / Haywood | Group 44 (USA) | | Jaguar | XJR-5 | | Jaguar | GTP |
| 45 | Paul, Jr. / Adam / Ganz | Conte Racing (USA) | | March | 85G | | Buick | GTP |
| 47 | Bohren / Bouchard / *Dingman | Dingman Brothers Racing (USA) | | Pontiac | Firebird | | Pontiac | GTO |
| 49 | Naon, Jr. / Vitolo / Garcia | Conrad Racing | | Porsche | 911 | | Porsche | GTU |
| 51 | McComb / Mancuso / Fiala | Mosler Racing | | Ferrari | 512 BB | /LM | Ferrari | GTO |
| 53 | Smith / Waugh / Febles | Mandeville Auto-Tech (USA) | Roger Mandeville | Mazda | RX-7 | | Mazda | GTO |
| 54 | Heinz / Barnett / Thompson / *Roshausen | Dave Heinz Imports (USA) | David Heinz | Chevrolet | Corvette | | Chevrolet | GTO |
| 55 | Peters / Schwarz / Schwartz | Preston & Son Enterprises | Walt Preston | Mazda | RX-7 | | Mazda | GTU |
| 57 | Zwiren / Pio Costa / Allison / Donnington | Zwiren Racing | Steve Zwiren | Mazda | RX-7 | | Mazda | GTU |
| 58 | Torres / Kravig / Hammond / *Borlase | Coin Operated Racing (USA) | Rick Borlase | Porsche | 934 | | Porsche | GTO |
| 60 | Swan / Ruth / Dietrich / *Brockman | Hobbit Racing | | Mazda | RX-7 | | Mazda | GTU |
| 61 | Shelton / Courtney / O'Neill | Team USA/Deco Sales (USA) | Brent O'Neill | Royale | RP40 | | Ford | GTP |
| 63 | Downing / Maffucci / Katayama | RGP 500 Racing (USA) | Jim Downing | Argo | JM16 | | Mazda | Lights |
| 64 | Soto / Rodriguez | Rene Rodriguez | | Chevrolet | Corvette | | Chevrolet | GTO |
| 65 | Dallenbach, Jr. / Jones / Bundy / *Ribbs | Roush Protofab (USA) | Jack Roush | Ford | Mustang | | Ford | GTO |
| 66 | Beasley / Lewis / Grantham | Bob Beasley (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 67 | Busby / Knoop / Mass | B.F. Goodrich (USA) | Jim Busby | Porsche | 962 | | Porsche | GTP |
| 68 | Halsmer / Morton / Quester | B.F. Goodrich (USA) | | Porsche | 962 | | Porsche | GTP |
| 69 | Hofstra / Slater | John Hofstra (USA) | | Porsche | 911 Carrera | RSR | Porsche | GTO |
| 70 | Cummings / Rubright / *Walker | Ormond Racing | Don Cummings | Chevrolet | Corvette | | Chevrolet | GTO |
| 71 | Johnson / Dunham / Terada | Team Highball (USA) | Amos Johnson | Mazda | RX-7 | | Mazda | GTU |
| 72 | Shafer / Nehl / Painter / *Silcox | Centurion Auto Trans | | Chevrolet | Camaro | | Chevrolet | GTO |
| 73 | Howey / Koch / Wolf | Wolf Engines (USA) | Tracy Wolf | Chevrolet | Camaro | II | Chevrolet | GTO |
| 74 | Gentilozzi / *Hill / *Godsey / *Akin | Whitehall Motorsports (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTU |
| 76 | Baldwin / Young / Kline | Malibu Grand Prix (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 77 | Wallace / Petrick / Sikes | Championship Motorsports (USA) | | Mazda | RX-7 | | Mazda | GTU |
| 78 | Garcia / Matienzo | Superior Racing Team (USA) | Raul Garcia | Pontiac | Firebird | | Pontiac | GTO |
| 79 | Winters / Bergstrom / Casey | Whitehall Motorsports (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTU |
| 80 | Bonnet / Derhaag / Lindley / *St. Lawrence | Lindley Motor LTD (USA) | Les Lindley | Chevrolet | Camaro | | Chevrolet | GTO |
| 81 | Alexander / Hill / Alderman | Mosler Racing | | Ferrari | 308 GTB | | Ferrari | GTU |
| 83 | Wessel / Whitaker / Kennedy / Keck | K & P Racing (USA) | Karl Keck | Chevrolet | Corvette | C3 | Chevrolet | GTO |
| 84 | Clay Young | Young Racing (USA) | Clay Young | Pontiac | Fiero | | Pontiac | GTU |
| 85 | Fittipaldi / Garcia / DeNarvaez | Ralph Sanchez Racing | | March | 85G | | Buick | GTP |
| 86 | Boutsen / Leven / Pescarolo | Bayside Disposal Racing (USA) | | Porsche | 962 | | Porsche | GTP |
| 87 | Forbes-Robinson / Schneider / Istook | Performance Motorsports (USA) | | Porsche | 924 | Carrera GTR | Porsche | GTU |
| 88 | Leven / Pescarolo / Boutsen | Bayside Disposal Racing (USA) | Bruce Leven | Porsche | 962 | | Porsche | GTP |
| 89 | "Jamsal" / Galdamez / "Anbagua" | Scorpio Racing (ES) | | Porsche | 934 | | Porsche | GTO |
| 90 | Delano / Petery / Riggins | Road Circuit Tech | | Pontiac | Firebird | | Pontiac | GTO |
| 92 | Gennone / Prego / Overbagh / Fuller | OMR Engines (USA) | Hoyt Overbagh | Chevrolet | Camaro | III | Chevrolet | GTO |
| 93 | Marsh / Pawley / Marsh | Mid-O/Rusty Jones (USA) | Don Marsh | Argo | JM16 | | Mazda | Lights |
| 94 | Phalf / Winfree / Hopkins | 49th Star Racing | | Porsche | 911 | | Porsche | GTU |
| 95 | Van Every / Tisdelle / Refenning | Van Every Racing (USA) | Ash Tisdelle | Porsche | 935 | | Porsche | GTP |
| 96 | Moffat / Hansford / Bartlett / McCloud | Allan Moffat Racing | | Mazda | RX-7 | | Mazda | GTO |
| 97 | Scyphers / Glick / Cooper | Scyphers-Ankor Racing (USA) | Billy Scyphers | Chevrolet | Corvette C4 | | Chevrolet | GTO |
| 99 | Cord / Aase | All American Racers (USA) | Dan Gurney | Toyota | Celica | Mk III | Toyota | GTU |