| 2 | Rodriguez / Yenko | Sunray DX Oil Company (USA) | | Chevrolet | Corvette | | Chevrolet | GT+5.0 |
| 3 | Sharp / Morgan / *Ausburn / *Dooley | Sunray DX Oil Company (USA) | | Chevrolet | Corvette | C3 | Chevrolet | GT+5.0 |
| 4 | Thompson / DeLorenzo / *Dooley | Sunray DX Oil Company (USA) | | Chevrolet | Corvette | | Chevrolet | GT+5.0 |
| 7 | Costanzo / Harris / Heinz | Slaton Chevrolet (USA) | | Chevrolet | Corvette Sting Ray | C2 | Chevrolet | GT+5.0 |
| 8 | Motschenbacher / Leslie / Guldstrand | American International (USA) | James Garner | Lola | T70 | Mk.3 GT | Chevrolet | S5.0 |
| 9 | Patrick / Jordan | American International (USA) | James Garner | Lola | T70 | Mk.3 GT | Chevrolet | S5.0 |
| 10 | Bonnier / Axelsson | Ecurie Bonnier (CH) | Joakim Bonnier | Lola | T70 | Mk.3 GT | Chevrolet | S5.0 |
| 11 | De Udy / Dibley | Mike de 'Udy (GB) | Michael De Udy | Lola | T70 | Mk.3 GT | Chevrolet | S5.0 |
| 12 | Jowett, Jr. / Cardwell | Wilton T. Jowett, Sr. (USA) | | Chevrolet | Camaro | I | Chevrolet | TA5.0 |
| 14 | Mastandrea / Noseda | Mar Shipping (USA) | | Chevrolet | Camaro | I | Chevrolet | TA5.0 |
| 15 | Donohue / Fisher | Roger Penske Racing (USA) | Roger Penske | Chevrolet | Camaro | I Z28 | Chevrolet | TA5.0 |
| 16 | Fisher / Welch / Johnson | Roger Penske Racing (USA) | | Chevrolet | Camaro | I Z28 | Chevrolet | TA5.0 |
| 17 | Chitwood / Horchler / Hoffman | Joie Chitwood, Jr. (USA) | | Chevrolet | Camaro | I | Chevrolet | TA5.0 |
| 18 | Corwin / Pipin | James Corwin (USA) | | Chevrolet | Camaro | I | Chevrolet | TA5.0 |
| 19 | Murphy / Moore | H.R.H. Corporation (USA) | | Chevrolet | Camaro | I | Chevrolet | TA5.0 |
| 20 | McClain / Boo | Padrick Chevrolet (USA) | David H. McClain | Chevrolet | Camaro | I Z28 | Chevrolet | TA5.0 |
| 21 | Yuma / Boye | Bill Boyé Racing (USA) | | Chevrolet | Camaro | I | Chevrolet | TA5.0 |
| 22 | Hagan / McVeigh / Gillebard | Billy Hagan (USA) | | Mercury | Cougar | I | Ford | TA5.0 |
| 23 | Jennings / Rainville / *Pettey | Squadra Course Verona (USA) | | Mercury | Cougar | I | Ford | TA5.0 |
| 24 | Revson / Scott / *Martin | Javelin Racing Team (USA) | | AMC | Javelin | | Rambler | TA5.0 |
| 25 | Follmer / Grant / Scott / *Martin | Javelin Racing Team (USA) | | AMC | Javelin | | Rambler | TA5.0 |
| 26 | Guthrie / Engeman | G.& H. Engineering (Ring-Free Racing Team) (USA) | | AMC | Javelin | | Rambler | TA5.0 |
| 27 | Kleinpeter / Hollander / Mummery | Port of Entry Motors (USA) | | Shelby | GT350 | | Ford | GT5.0 |
| 28 | Ickx / Redman | J. W. Engineering (GB) | | Ford | GT40 | | Ford | S5.0 |
| 29 | Hawkins / Hobbs | J. W. Engineering (GB) | | Ford | GT40 | | Ford | S5.0 |
| 30 | Piper / Nelson | Edward Nelson Racing (GB) | Edward Nelson | Ford | GT40 | | Ford | S5.0 |
| 31 | Titus / Bucknum | Shelby Racing (USA) | Carroll Shelby | Ford | Mustang | | Ford | TA5.0 |
| 32 | Moffat / Kwech / *Follmer | Shelby Racing (USA) | Carroll Shelby | Ford | Mustang | | Ford | TA5.0 |
| 33 | McComb / Richards / *Tullius / *Dooley | John McComb (USA) | | Ford | Mustang | | Ford | TA5.0 |
| 34 | Posey / Minter | Mathews Racing Team (USA) | | Ford | Mustang | | Ford | TA5.0 |
| 35 | Grossman / Dini | Randy's Auto Body (USA) | | Ford | Mustang | | Ford | TA5.0 |
| 36 | Novoa / van Beuren, Jr. / *Perez Gama | Dos Caballos Racing (MEX) | | Ford | Mustang | | Ford | TA5.0 |
| 37 | Wintersteen / Starr | Starr Racing (USA) | | Ford | Mustang | | Ford | TA5.0 |
| 38 | Favreau / Amiot | Gagnon Spring, Inc. (CDN) | | Ford | Mustang | | Ford | TA5.0 |
| 39 | Merello / Ortega / Gunn | Raceco (USA) | | Ferrari | 250 LM | | Ferrari | S5.0 |
| 42 | Bianchi / Grandsire | Societé Alpine (F) | | Alpine | A211 | | Renault | P3.0 |
| 44 | Hopkirk / Hedges | British Motor Company (GB) | | MG | C | | BMC | P3.0 |
| 47 | Dittemore / Tullius / *Rothschild | Leyland Motor Corporation (USA) | | Triumph | TR250 | K | Triumph | P3.0 |
| 48 | Mitter / Stommelen | Porsche Automobile Co. (D) | | Porsche | 907 | | Porsche | P3.0 |
| 49 | Siffert / Herrmann | Porsche Automobile Co. (D) | | Porsche | 907 | | Porsche | P3.0 |
| 50 | Scarfiotti / Buzzetta / *Neerpasch | Porsche Automobile Co. (D) | | Porsche | 907 | | Porsche | P3.0 |
| 51 | Elford / Neerpasch | Porsche Automobile Co. (D) | | Porsche | 907 | | Porsche | P3.0 |
| 52 | Cline / Pickering | Richard P. Cline (USA) | | Triumph | GT6 | | BMC | GT2.0 |
| 55 | Capriles / Atencio | Raceco (USA) | | Porsche | 906 | E | Porsche | P2.0 |
| 56 | Foitek / Lins | Valvoline Oil Company (CH) | | Porsche | 910 | | Porsche | P2.0 |
| 57 | McDaniel / Sullivan | H.R.H. Engineering (USA) | | Porsche | 911 | R | Porsche | P2.0 |
| 58 | Steinemann / Spoerry | Squadra Tartaruga (CH) | | Porsche | 910 | | Porsche | P2.0 |
| 59 | Kirby / Johnson | Don Burns V.W. (USA) | Don Burns | Porsche | 911 | S | Porsche | GT2.0 |
| 60 | Harrison / Loomis / Ryan | Gregg Loomis (USA) | | Porsche | 911 | S | Porsche | GT2.0 |
| 61 | Duval / Kroll | Jacques Duval (CDN) | | Porsche | 911 | S | Porsche | GT2.0 |
| 62 | Hanrioud / Garant | Jean Pierre Hanrioud (F) | | Porsche | 911 | S | Porsche | GT2.0 |
| 63 | Greger / Huth | Sepp Greger (D) | | Porsche | 911 | Coupé | Porsche | GT2.0 |
| 64 | Bailey / Locke | B.& B. Motors (USA) | | Porsche | 906 | | Porsche | S2.0 |
| 66 | Rodrigues / McDaniel / Brack | British Motor Company (GB) | | MG | B | GT | BMC | GT2.0 |
| 67 | Gammon / Waldron / Scott | Waldron Motors (USA) | | MG | B | | BMC | GT2.0 |
| 68 | Sylvia / Domizi / Fogle | Dyno Racing (USA) | | Lotus | 47 | | Ford | S1.6 |
| 69 | Hugus / Dietrich | Elsco BMW (USA) | | Lotus | 47 | | BMW | P2.0 |
| 70 | Nearburg / Jett | Elsco BMW (USA) | | Lotus | 47 | | BMW | P2.0 |
| 71 | Maglioli / Everett / Andersson | H.F. Squadra (Algar Enterprises) (I) | | Lancia | Fulvia | Sport | Lancia | P2.0 |
| 72 | Pinto / Taramazzo / Maglioli | H.F. Squadra (Algar Enterprises) (I) | | Lancia | Fulvia | HF | Lancia | P2.0 |
| 73 | Baker / Garton | Donald Healey Motor Co. LTD. (GB) | | Austin-Healey | Sprite | | BMC | P2.0 |
| 74 | Truitt / Canfield | Donald Healey Motor Co. LTD. (GB) | | MG | Midget | | BMC | S1.6 |
| 76 | Thompson / Lowther / Heppenstall | Howmet Corporation (USA) | | Howmet | TX | | Continental | P3.0 |
| 80 | Torpy / Keenan | William H. Laughlin (USA) | | Chevrolet | Corvette | | Chevrolet | GT+5.0 |
| 81 | Unser / Ruby | Samadco Ltd. (Smokey Yunick) (EC) | | Chevrolet | Camaro | I | Chevrolet | TA5.0 |
| 84 | Rodgers / Robson / *Buchman | Coquina Motors (USA) | Richard Robson | Jaguar | E-type | | Jaguar | GT5.0 |
| 85 | Mims / Summers | Best Sports Cars (USA) | | Yenko | Stinger | | Chevrolet | P3.0 |
| 86 | Witt / Vega / Cameron | John Cameron (USA) | | Triumph | TR4 | A | Triumph | GT3.0 |
| 90 | Bencker / Pickett / Newman | William Bencker (USA) | | Porsche | 911 | | Porsche | GT2.0 |
| 91 | Oest / Feinstein / Newman | Dieter Oest (USA) | | Porsche | 356 | B 2000 GS Carrera 2 | Porsche | GT2.0 |
| 93 | Mollin / Riley / Cone | Arthur Mollin Racing (USA) | | TVR | Grantura | Mk IV | BMC | S2.0 |
| 95 | Cohn / Pickett / Lilly | Arthur Cohn (USA) | | Beach | Prototype | | VW | P2.0 |
| 96 | Kondracki / Andrews, Jr. | Richard P. Cline (USA) | | Triumph | Spitfire | | BMC | GT2.0 |