| 1st | 6 | Donohue / Hobbs | Ferrari 512 M | Penske/White Racing | 2:31.6500 | 198.6606 |
| 2nd | 25 | Andretti / Ickx | Ferrari 312 PB | Ferrari Automobili | 2:32.4700 | |
| 3rd | 2 | Rodriguez / Oliver | Porsche 917 K | J. W. Automotive Engineering Ltd. | 2:33.8400 | |
| 4th | 3 | Elford / Larrousse | Porsche 917 K | Martini & Rossi Racing | 2:34.8100 | |
| 5th | 33 | Galli / Stommelen | Alfa Romeo T33/3 | Autodelta S.p.a. | 2:34.9900 | |
| 6th | 1 | Siffert / Bell | Porsche 917 K | J. W. Automotive Engineering Ltd. | 2:35.1800 | |
| 7th | 22 | Revson / Savage | Ferrari 512 M | North American Racing Team | 2:35.5000 | |
| 8th | 20 | Gregory / Young | Ferrari 512 M | Young American Racing Team | 2:37.4000 | |
| 9th | 23 | Bucknum / Posey | Ferrari 512 S | North American Racing Team | 2:39.3700 | |
| 10th | 34 | Vaccarella / Hezemans | Alfa Romeo T33/3 | Autodelta S.p.a. | 2:39.8500 | |
| 11th | 32 | de Adamich / Pescarolo / Vaccarella | Alfa Romeo T33/3 | Autodelta S.p.a. | 2:40.1700 | |
| 12th | 26 | Parsons / Weir | Ferrari 512 S | North American Racing Team | 2:43.8000 | |
| 13th | 61 | Kleinpeter / Belcher | Lola T210 Ford | Promotional Advertising Corp. | 2:54.7200 | |
| 14th | 11 | Yenko / DeLorenzo / Thompson | Chevrolet Corvette | Troy Promotions, Inc. | 2:56.5200 | |
| 15th | 21 | Chinetti, Jr. / Eaton | Ferrari 312 P/71 | North American Racing Team | 2:56.8000 | |
| 16th | 48 | Greenwood / Smothers | Chevrolet Corvette | John Greenwood | 2:57.7700 | |
| 17th | 12 | Thompson / Mahler | Chevrolet Corvette | Troy Promotions, Inc. | 2:58.9600 | |
| 18th | 50 | Barker / Harrington | Chevrolet Corvette | John Greenwood | 3:00.1100 | |
| 19th | 16 | Rinzler / Baker | Chevron B16 Ford | Ring-Free Oil Racing Team | 3:02.8600 | |
| 20th | 57 | Heinz / Johnson / Costanzo | Chevrolet Corvette | Dave Heinz Racing, Inc. | 3:03.1100 | |
| 21st | 17 | Fraser / Reynolds / Sage / Baker | Chevron B16 Ford | Ring-Free Oil Racing Team | 3:03.2200 | |
| 22nd | 58 | Rahal / Frank / Wise | Porsche 906 | Nationwide Food Brokers Racing Team | 3:03.7900 | |
| 23rd | 86 | Gottlob / Lowther / *Nagel | Chevrolet Corvette | Cliff Gottlob | 3:06.1000 | |
| 24th | 74 | Rosen / Jacobs | Porsche 906 | Dr. Mervin B. Rosen | 3:06.4600 | |
| 25th | 71 | Gimondo / Dietrich | Chevrolet Camaro II | Takondo Racing | 3:07.9300 | |
| 26th | 56 | Greger / Weigel | Porsche 907 | Josef Greger | 3:07.9700 | |
| 27th | 47 | Tremblay / McDill | Chevrolet Camaro | Bruce Behrens Racing | 3:08.5400 | |
| 28th | 59 | Gregg / Haywood | Porsche 914/6 | Brumos Porsche Audi Corp. | 3:10.7200 | |
| 29th | 72 | Mitchell / Kemp | Chevrolet Camaro | Robert R. Mitchell | 3:12.5000 | |
| 30th | 28 | Meaney / Wright / Laucks | Porsche 914/6 | Ralph Meaney, Inc. | 3:13.8100 | |
| 31st | 29 | Behr / Conrad / Buffum | Porsche 914/6 | Ralph Meaney, Inc. | 3:16.5100 | |
| 32nd | 92 | Cordts / Pike | Chevrolet Camaro | B. F. Goodrich Tire Co. | 3:16.6900 | |
| 33rd | 31 | Locke / Everett | Porsche 911 T | Locke Lake Colony & Waterville Estates | 3:16.9800 | |
| 34th | 89 | Gafford / Smith | Chevrolet Camaro | H. Houghton Smith | 3:19.9400 | |
| 35th | 18 | Guthrie / Smith / *Birrell | Chevron B16 Ford | Ring-Free Oil Racing Team | 3:20.4800 | |
| 36th | 15 | Keyser / Jennings | Porsche 911 S | Toad Hall Racing | 3:20.5800 | |
| 37th | 19 | Ciccone / Greenhalgh / Roberts | Chevrolet Camaro | Thomas T. Ciccone, Jr. | 3:21.5700 | |
| 38th | 46 | Gray / Keller / Magnor | Ford Mustang | Sebring Racing, Inc. | 3:22.2800 | |
| 39th | 5 | Duval / Nicholas / Bailey | Porsche 914/6 | Jacques Duval | 3:22.4300 | |
| 40th | 14 | Canada / Christiansen | Chevrolet Camaro | Boykin Auto Repair | 3:23.5000 | |
| 41st | 38 | Quintana / Belperche / Almeida | Shelby GT500 | John P. Belperche | 3:24.1200 | |
| 42nd | 24 | Cluxton / Grossman | Ferrari 365 GTB/4 | North American Racing Team | 3:24.4800 | |
| 43rd | 39 | Tisdelle / Kirill | Porsche 911 S | K&T Enterprises | 3:25.4300 | |
| 44th | 42 | Sereix / Garcia / Noseda | Chevrolet Camaro II | Garcia Racing | 3:25.6500 | |
| 46th | 54 | Arutunoff / Pryor / Goellnicht | Abarth 2000 SP (SE010) | Automobiles of Italy, Inc. | 3:25.7900 | |
| 45th | 88 | Oliver / Maynard / Flanagan | Chevrolet Camaro I | S-Car-Go-Racing | 3:25.8700 | |
| 48th | 45 | Pettey / Dutton | Ford Mustang | Reventlow-Pettey Automobiles | 3:26.8400 | |
| 47th | 35 | Wilson / Collins | Chevrolet Camaro | Collins-Wilson Racing Ent. | 3:27.4900 | |
| 49th | 43 | Garcia / Gonzalez / Mastandrea | Chevrolet Chevy II | Garcia Racing | 3:27.4900 | |
| 50th | 63 | Elliott / Gwynne | Chevrolet Camaro I | Preston Hood Chevrolet | 3:28.9500 | |
| 51st | 60 | Walker / Springer | Porsche 911 S | Wheel Sport, Ent. | 3:29.2800 | |
| 52nd | 66 | Small / Fordyce / *Lipke | Chevrolet Camaro I | Performance Automobile | 3:30.0800 | |
| 53rd | 51 | Gammon / Donley / *Garza | MGB | Waldron Motors Racing Team | 3:30.1100 | |
| 54th | 40 | Hotchkis / Kirby | Porsche 911 S | Bozzani Porsche, Inc. | 3:31.2400 | |
| 55th | 52 | Scott / Lanier / Houser | MGB | Waldron Motors Racing Team | 3:31.3500 | |
| 56th | 81 | Walle / Davey / Reddy | Porsche 911 S | Ray Walle Ent. Inc. | 3:32.4300 | |
| 57th | 84 | Goldleaf / Taylor / Wheat | Alfa Romeo GTV | Del Taylor | 3:32.5100 | |