| 1st | 25 | Amon / Andretti | Ferrari 312 P | Ferrari S.P.A. SEFAC | 2:40.140 | 2:40.1400 |
| 2nd | 9 | Bucknum / Donohue | Lola T70 Mk.3B GT Chevrolet | Roger Penske Racing Enterprises | 2:40.920 | 2:40.9200 |
| 3rd | 29 | Mitter / Schütz | Porsche 908/02 | Porsche System Engineering Ltd. | 2:42.770 | 2:42.7700 |
| 4th | 31 | Siffert / Redman | Porsche 908/02 | Porsche System Engineering Ltd. | 2:42.900 | 2:42.9000 |
| 5th | 30 | Elford / Attwood | Porsche 908/02 | Porsche System Engineering Ltd. | 2:43.190 | 2:44.3800 |
| 6th | 10 | Patrick / Jordan | Lola T70 Mk.3 GT Chevrolet | American International Racing, Inc. | 2:43.440 | 2:43.4400 |
| 7th | 11 | Motschenbacher / Leslie | Lola T70 Mk.3 GT Chevrolet | American International Racing, Inc. | 2:44.050 | 2:44.0500 |
| 8th | 31T | Larrousse / Maglioli | Porsche 908/02 | Porsche System Engineering | 2:44.360 | 2:44.3600 |
| 9th | 14 | Norinder / Bonnier | Lola T70 Mk.3B GT Chevrolet | Sportscars Switzerland | 2:44.370 | 2:44.3700 |
| 10th | 28 | Herrmann / Ahrens, Jr. / Stommelen | Porsche 908/02 | Porsche System Engineering Ltd. | 2:44.510 | 2:44.5100 |
| 11th | 32 | Casoni / de Adamich / *Surtees | Alfa Romeo T33/3 | Autodelta, S.P.A. | 2:45.640 | 2:45.6400 |
| 12th | 27 | Stommelen / Buzzetta / Ahrens, Jr. | Porsche 908/02 | Porsche System Engineering Ltd. | 2:45.670 | 2:45.6700 |
| 13th | 22 | Oliver / Ickx | Ford GT40 | J. W. Automotive Engineering Ltd. | 2:47.430 | 2:47.4300 |
| 14th | 23 | Hobbs / Hailwood | Ford GT40 | J. W. Automotive Engineering Ltd. | 2:47.740 | 2:47.7400 |
| 15th | 33 | Vaccarella / Bianchi | Alfa Romeo T33/3 | Autodelta, S.P.A. | 2:47.950 | 2:47.9500 |
| 16th | 34 | Galli / Giunti / *Casoni | Alfa Romeo T33/3 | Autodelta, S.P.A. | 2:51.360 | 2:51.3600 |
| 17th | 44 | Soler-Roig / Lins | Porsche 907 2.2 | Escuderia Nacional C.S. | 2:54.550 | 2:54.5500 |
| 18th | 1 | DeLorenzo / Thompson / *McConkey | Chevrolet Corvette | Troy Promotions, Inc. | 3:00.300 | 3:00.3000 |
| 19th | 45 | Baker / Smothers | Porsche 906 E | Smothers Brothers Racing Team | 3:01.130 | 3:01.1300 |
| 20th | 26 | Rodriguez / Parsons | Ferrari 250 P | N.A.R.T. | 3:01.360 | 3:01.3600 |
| 21st | 2 | Lang / Hufstader | Chevrolet Corvette | Troy Promotions, Inc. | 3:01.590 | 3:01.5900 |
| 22nd | 4 | Costanzo / Heinz | Chevrolet Corvette | Or Costanzo | 3:02.270 | 3:02.2700 |
| 23rd | 5 | Yenko / Grossman / *Guldstrand | Chevrolet Camaro Z/28 | Best Photo Service | 3:03.210 | 3:03.2100 |
| 24th | 3 | Lowther / Esseks / Dominianni | Chevrolet Corvette | Robert D. Esseks | 3:03.890 | 3:03.8900 |
| 25th | 18 | Jowett, Jr. / Tullius | Chevrolet Camaro | Wilton T. Jowett, Srov. | 3:05.920 | 3:05.9200 |
| 26th | 37 | Rodriguez / Kolb / *Posey | Ferrari Dino 206 S | N.A.R.T. | 3:07.240 | 3:07.2400 |
| 27th | 46 | Capriles / Atencio / *Maratos | Porsche 906 E | Escuderia Manana | 3:07.360 | 3:07.3600 |
| 28th | 17 | Gimondo / Tremblay | Chevrolet Camaro I | Bruce Behrens Racing Enterprises | 3:09.140 | 3:09.1400 |
| 29th | 57 | Maglioli / Kleinpeter / Beatty | Chevron B8 BMW | Raceco | 3:09.490 | 3:09.4900 |
| 30th | 38 | Posey / Dini / *Rodriguez | Ferrari Dino 206 GT | N.A.R.T. | 3:11.270 | 3:11.2700 |
| 31st | 48 | Rahal / Stroh / Wise | Porsche 906 | Nationwide of Chicago Food Brothers, Inc. | 3:12.330 | 3:12.3300 |
| 32nd | 21 | Dent / Bock | Chevrolet Camaro | Larry Drover, (Laural Racing) | 3:12.570 | 3:12.5700 |
| 33rd | 24 | Grant / Oest | Ford GT40 | Auto Enterprizes | 3:13.450 | 3:13.4500 |
| 34th | 20 | McClain / Kerney | Chevrolet Camaro | David H. McClain | 3:14.190 | 3:14.1900 |
| 35th | 19 | Carter / Adams | Chevrolet Camaro | Maurice Carter Chevrolet | 3:17.270 | 3:17.2700 |
| 36th | 50 | Duval / Nicholas | Porsche 911 T | Grand Prix Motor Oil | 3:17.460 | 3:17.4600 |
| 37th | 90 | Netterstrom / Jennings / Downs | Porsche 911 | P.A.R.T. | 3:19.710 | 3:19.7100 |
| 38th | 47 | Bailey / Locke / *Jennings | Porsche 911 T | P.A.R.T. | 3:20.370 | 3:20.3700 |
| 39th | 52 | Larrousse / Wicky / Sage | Porsche 911 T | Wicky Racing Team | 3:20.640 | 3:20.6400 |
| 40th | 51 | Loomis / Harrison / Ryan | Porsche 911 S | RBM Motors | 3:20.930 | 3:20.9300 |
| 41st | 53 | Pickett / Gregg | Porsche 911 | Wilbur Pickett | 3:21.160 | 3:21.1600 |
| 42nd | 94 | Ormes / Mastandrea | Chevrolet Camaro | Norberto Mastandrea (Freeport Bahama Racing Team) | 3:24.120 | 3:24.1200 |
| 43rd | 36 | Brack / Hill | MGC | British Leyland Motor Corporation | 3:26.740 | 3:26.7400 |
| 44th | 43 | Heppenstall / Brown | Heppenstall Special Volkswagen | LeHigh Acres | 3:27.040 | 3:27.0400 |
| 45th | 16 | Stevens / Barg | Chevrolet Camaro | Richard Stevens | 3:27.140 | 3:27.1400 |
| 46th | 84 | Drolsom / Williamson | Porsche 911 | Dr. Harold Williamson | 3:27.210 | 3:27.2100 |
| 47th | 58 | Hugus / Dietrich / Nearburg | BMW 2002 | Elsco Corporation | 3:27.530 | 3:27.5300 |
| 48th | 65 | Maglioli / Pinto | Lancia Fulvia Sport Competizione | Algar Enterprises, Inc. | 3:29.000 | 3:29.0000 |
| 49th | 71 | Baker / Richards / Baker | Austin-Healey Sprite | Ring Free Oil Racing Team | 3:30.280 | 3:30.2800 |
| 50th | 35 | Hedges / Hopkirk | MGC GT | British Leyland Motor Corporation | 3:30.310 | 3:30.3100 |
| 51st | 54 | Sanford / Opert | Porsche 911 | Fred Opert | 3:30.650 | 3:30.6500 |
| 52nd | 61 | Samm / Parks / Colgate | Lotus 47 | Gerry Racing Enterprise, Inc. | 3:30.780 | 3:30.7800 |
| 53rd | 66 | Ireland / Tillson / Hanna | Lancia Fulvia Coupé 1,6HF | Algar Enterprises, Inc. | 3:35.430 | 3:35.4300 |
| 54th | 59 | Drolet / Smith | BMW 2002 | Elsco Corporation | 3:35.570 | 3:35.5700 |
| 55th | 63 | Gammon / Mummery / Houghton | MGB | Waldron Motors | 3:38.130 | 3:38.1300 |
| 56th | 72 | Guthrie / Mims / Engeman | Austin-Healey Sprite | Ring Free Oil Racing Team | 3:40.200 | 3:40.2000 |
| 57th | 68 | Scott / McDaniel / Pieper | Zink VSR Volkswagen | H.R.H. Corp. | 3:41.030 | 3:41.0300 |
| 58th | 64 | Waldron / Scott / Donley | MGB | Waldron Motors | 3:42.820 | 3:42.8200 |
| 59th | 88 | Blessing / Cummings / Stumes | Shelby GT350 | Donald C. Cummings | 3:43.520 | 3:43.5200 |
| 60th | 49 | Rosen / Morrell | Porsche 906 | Dr. Merv Rosen | 3:43.710 | 3:43.7100 |
| 61st | 69 | Smith / Lilly / Pickett / *Howard | Lotus Europa | John F. Howard | 3:46.330 | 3:46.3300 |
| 62nd | 62 | Blackburn / Truitt | MGB GT | British Leyland Motor Corporation | 3:47.120 | 3:47.1200 |
| 63rd | 73 | Cameron / Kemmerer / *Phillips | Austin-Healey Sprite | Arthur Tuckerman | 3:48.310 | 3:48.3100 |
| 64th | 99T | Colgate / Parks / *Hopkirk / *Hedges / *Brack / *Hill / *Truitt / *Blackburn | MGB | Gerry Racing Enterprise, Inc. | 3:52.180 | 3:52.1800 |
| 65th | 41 | DeAmbadgio / Trevale / *Sandoval | Alfa Romeo GTA Junior | Escuderia Manana | 3:55.950 | 3:55.9500 |
| 66th | 85 | Crebs / Strickler / Whitaker | Alfa Romeo GTA | Richard Crebs | 4:02.290 | 4:02.2900 |
| 67th | 60 | Brown / Marcus | Opel Rallye | Jim Cooke Buick & Opel | 4:08.090 | 4:08.0900 |
| 68th | 67 | Boye / Shirey | Beach 4B Volkswagen | Competition Components | 4:21.410 | 4:21.4100 |