| 5 | May / Allison | Robert Harper | Robert Harper | Chevrolet | Corvair | | Chevrolet | GT3.0 |
| 6 | Guldstrand / Moore / Wintersteen | Roger Penske (USA) | | Chevrolet | Corvette Sting Ray | C2 | Chevrolet | GT+3.0 |
| 7 | Bolander / Winkelmann / Olson | John Olson | | Ford | Cortina | GT | Ford | P2.0 |
| 12 | Hull / Byrne / Kingham | Jaguar of Florida | | Jaguar | E-type | | Jaguar | GT+3.0 |
| 14 | Gregg / Drolsom | Brumos Porsche Florida (USA) | Peter Gregg | Porsche | 904 | GTS | Porsche | S2.0 |
| 15 | Herrmann / Linge | Porsche System Engineering (D) | | Porsche | 906 | | Porsche | P2.0 |
| 16 | Mitter / Buzzetta | Porsche System Engineering (D) | | Porsche | 904 | GTS | Porsche | S2.0 |
| 17 | Klass / Schütz | Porsche System Engineering (D) | | Porsche | 904 | GTS | Porsche | S2.0 |
| 18 | Ryan / Coleman / Bencker | RBM Motors (USA) | Jack Ryan | Porsche | 911 | | Porsche | GT2.0 |
| 19 | Forlong / Dieas / McClain | Dave McClain | | Porsche | 356B Super 90 | | Porsche | GT1.6 |
| 20 | Posey / Haynes / Theodoracopulos | Sam Posey | | Porsche | 904 | GTS | Porsche | S2.0 |
| 21 | Rodriguez / Andretti | North American Racing Team (USA) | | Ferrari | 365 P2 | | Ferrari | P+2.0 |
| 22 | Rindt / Bondurant | North American Racing Team (USA) | | Ferrari | 250 LM | | Ferrari | P+2.0 |
| 23 | Konig / Clarke / Hurt | Peter Clarke (GB) | | Ferrari | 250 LM | | Ferrari | P+2.0 |
| 24 | Ireland / Hailwood / Drummond | Drummond Racing Organisation (GB) | George Drummond | Ferrari | 250 LM | | Ferrari | P+2.0 |
| 25 | Bianchi / Langlois van Ophem / "Beurlys" | Ecurie Francorchamps | | Ferrari | 365 P2 | | Ferrari | P+2.0 |
| 26 | "Eldé" / Ickx / *"Beurlys" | Ecurie Francorchamps (B) | | Ferrari | 250 LM | | Ferrari | P+2.0 |
| 27 | Piper / Attwood | David Piper (GB) | | Ferrari | 250 LM | | Ferrari | P+2.0 |
| 28 | Hulme / Wilson | Team Chamaco Collect (GB) | | Ferrari | 250 LM | | Ferrari | P+2.0 |
| 29 | Hawkins / Epstein | Epstein Enterprises Ltd. (GB) | | Ferrari | 250 LM | | Ferrari | S+3.0 |
| 30 | Perkins / Slottag / *Beazell | Jack Slottag | | Ferrari | 250 GTO | | Ferrari | S3.0 |
| 31 | Fulp / Rutan / Jennings | John Fulp | | Ferrari | 330 P | | Ferrari | P+2.0 |
| 32 | Follmer / Wester / Hawkins | North American Racing Team | | Ferrari | 250 LM | | Ferrari | P+2.0 |
| 36 | Pickett / Bean | Cannon Auto | | Alfa Romeo | Giulia Zagato | | Alfa Romeo | S1.6 |
| 40 | Waltman / Swanson / Cone | Genser Forman | | Triumph | TR4 | | Triumph | GT3.0 |
| 41 | Kleinpeter / Fry / Parsons | E. P. Drescher (USA) | | Triumph | LM | | Triumph | P2.0 |
| 42 | Hughes / Salo / Addison | John Addison (USA) | | Triumph | TR4 | | Triumph | GT3.0 |
| 43 | Kelder / Dube / Wilson | Cannon Auto (USA) | | Triumph | TR4 | A | Triumph | GT3.0 |
| 44 | Croucher / Glenn / Eve | Kenneth G. Chambliss | | MG | B | | BMC | GT2.0 |
| 45 | Byrne / Vega | John Kingham | | Triumph | TR4 | A | Triumph | GT3.0 |
| 47 | Lane / Sesslar | David Lane | | Porsche | 904 | GTS | Porsche | S2.0 |
| 54 | Stoutenburg / Jones / Isley | Raymond Stoutenburg | | Plymouth | Barracuda | | Plymouth | GT+3.0 |
| 55 | Weaver / Fraim / Freeman | J. Randall | | Lotus | Elan | | Ford | GT1.6 |
| 56 | Maxwell / Martin | William J. Martin | | Volvo | P1800 | | Volvo | S2.0 |
| 59 | Yenko / Forte / Riley | Art Riley (USA) | | Volvo | P1800 | A | Volvo | S2.0 |
| 65 | Bonnier / Hill | Chaparral Cars Inc. (USA) | | Chaparral | 2D | | Chevrolet | P+2.0 |
| 67 | Cornelius / Boo / Brown | Cannon Auto | | Chevrolet | Corvette Sting Ray | | Chevrolet | GT+3.0 |
| 73 | McKemie / Petmecky / Opert | Fred Opert (USA) | | Elva | Courier | Mk IV | Ford | S2.0 |
| 74 | Hess / Hess | Queen City Rambler | | Rambler | Marlin | | | P+2.0 |
| 75 | Riley / MacGrotty | McMillan Ring Free Oil Co. (USA) | | Yenko | Stinger | | Chevrolet | P+2.0 |
| 77 | Bentley / Hill | Space Science | | Sunbeam | Tiger | | Ford | GT+3.0 |
| 78 | Smith / Drolet | Autosport (USA) | | Sunbeam | Alpine | | Sunbeam | S2.0 |
| 79 | Richards / Cuomo | Autosport | | Austin-Healey | Sprite | | BMC | P2.0 |
| 80 | Mims / Guthrie / Dietrich | Autosport (USA) | | Sunbeam | Alpine | | Sunbeam | S1.6 |
| 84 | Scott / Flanagan / Chastain | Pompano Sports Cars | | Alfa Romeo | Giulia Sprint GT | | Alfa Romeo | GT1.6 |
| 85 | Clark / Crow / Arutunoff | Anatoly Arutunoff (USA) | | Alfa Romeo | Giulia Sprint GT | | Alfa Romeo | GT1.6 |
| 86 | Sutcliffe / Grossman | Ford Advanced Vehicles | | Ford | GT40 | | Ford | S+3.0 |
| 87 | Ginther / Bucknum | Holman & Moody (USA) | | Ford | Mk II | | Ford | P+2.0 |
| 88 | Wonder / Wetanson | Bill Wonder (USA) | | Ford | GT40 | | Ford | S+3.0 |
| 89 | Gerber / Johnson / Lerch | Dan Gerber (USA) | | Shelby | Cobra | | Ford | S+3.0 |
| 90 | Kearney / Reina | Michael Reina (USA) | | Shelby | GT350 | | Ford | GT+3.0 |
| 91 | Thompson / Scott / Revson | Essex Wire Corporation | | Ford | GT40 | | Ford | S+3.0 |
| 92 | Revson / Gregory / Lowther | Essex Wire Corporation (USA) | | Ford | GT40 | | Ford | S+3.0 |
| 93 | Keck / Koveleski / Lowther | Scuderia Bear | | Shelby | Cobra | | Ford | S+3.0 |
| 94 | Noseda / Clark / Thorpe / Heuer | Ralph Noseda (USA) | | Shelby | Cobra | | Ford | S+3.0 |
| 95 | Hansgen / Donohue | Holman & Moody (USA) | | Ford | Mk II | | Ford | P+2.0 |
| 96 | Amon / McLaren | Shelby American Inc. (USA) | | Ford | Mk II | | Ford | P+2.0 |
| 97 | Gurney / Grant | Shelby American Inc. (USA) | | Ford | Mk II | | Ford | P+2.0 |
| 98 | Miles / Ruby | Shelby American Inc. (USA) | | Ford | Mk II | | Ford | P+2.0 |
| 99 | West / Macon | Joe Treadwell | | Ford | Mustang | | Ford | GT+3.0 |