The 1970 12 Hours of Sebring was an endurance race held at the 5.2 mile (8.3 km) Sebring International Raceway, Sebring, Florida, United States on March 21, 1970. It was the twentieth running of the endurance classic and the second round of the 1970 World Sportscar Championship season.

Pre-race With the 1969 to 1971 rules allowing sportscars with 5-litre-engines if at least 25 were made, which did Porsche early in 1969 with the Porsche 917 and Ferrari late in the year with the Ferrari 512S, up to 50 V12-powered race cars were available for the 1970 World Sportscar Championship endurance racing season, entered either by factory-backed teams, or by independent customers if they could find funding and pilots that could handle a 500+ hp car competitively for at least six hours, or up to 24h in some events.

John Wyer's Gulf-Porsche team had just come fresh off a 1-2 victory at the 1970 24 Hours of Daytona 7 weeks earlier. So far, Porsche was ahead in the championship against their only real rival, Ferrari. When the teams descended upon the isolated and very bumpy 5.2 mile Sebring airfield circuit in central Florida, qualifying was a mix of Ferraris and Porsches: American Mario Andretti qualified the #19 works Ferrari 512S Spyder on pole position at 121 mph at 2:33.5- 5 mph and 6.5 seconds faster than Chris Amon's time the year previous in a works 3-litre Ferrari 312P prototype and almost a second ahead of the #14 Jo Siffert/Brian Redman Gulf-Porsche 917K. Following them were the Porsche/Audi USA sponsored Porsche 917K driven by Vic Elford and Kurt Ahrens Jr., the #20 works Ferrari 512S Spyder of Jacky Ickx/Peter Schetty, the #15 Gulf-Porsche 917K of Pedro Rodríguez/Leo Kinnunen, and a NART-entered Ferrari 512S Spyder of Sam Posey/Ronnie Bucknum and the #21 works Ferrari 512S of Ignazio Giunti/Nino Vaccarella.

Race The 1970 running is considered by many to be the best 12 Hours of Sebring ever. This was the first 12 Hours of Sebring where the cars used a rolling start, a procedure similar to the start which is used at the Indianapolis 500, and has been used at every Sebring 12 Hours to this day. Before 1970, the drivers did a traditional Le Mans start, but the events of the 1969 Le Mans race in which English driver John Woolfe was killed driving his Porsche 917 after a crash in which he did not have his seatbelts fastened led the governing body to ban Le Mans starts on grounds of safety.

A group of 5-liter entries led away; Andretti led from pole position, followed by Siffert, Elford, Ickx, Rodriguez and the rest of the field, which included works Matra and Alfa Romeo prototypes, running in the 3-liter class. There was an accident between two Lolas- Bob Brown in the #26 car would continue, but Mike De Udy in the other Lola would retire after just one lap.

Ickx then moved ahead of Elford into 3rd, behind Siffert and Andretti, the former setting a fastest lap of 2:32.77 in an effort to catch Andretti, and he did for 2 laps- but Andretti regained it then lost it again when he pitted for fuel and a driver change. Other teams stopped for fuel and driver changes, as Andretti switched out with Merzario and Siffert with Redman. The #19's stop dropped it down to 5th, and moments later, Redman brought in the #14 car with electrical trouble. It was a lengthy pitstop, and the car dropped down the order. The order now was the #15 Porsche 917K of Rodriguez/Kinnunen, #16 Porsche 917K of Elford/Ahrens Jr, and the 3 works Ferraris. Near the 3rd hour, Rodriguez brought the leading car into the pits with a puncture. Although they were able to change the punctured tire and send Rodriguez out again, it was 4 laps behind the leading #19 Ferrari. The #16 car crashed and was out of the race with irreparable suspension damage. The Porsche 917K's problems allowed all three works Ferraris to lead the field into the night. And running in 5th place was a Solar Productions/Gulf sponsored #48 Porsche 908/02 of movie star and racer Steve McQueen (whose leg was in a cast) and Peter Revson, who was battling with the #33 works Alfa Romeo T33/3 of Toine Hezemans/Masten Gregory.

When night fell, the #20 Ickx/Schetty Ferrari went out after 151 laps with a blown head gasket, and the #21 Giunti/Vaccarella car was in the pits being repaired. Although the #19 Andretti/Merzario was still leading, and the #14 Redman/Kinnunen car, which had suffered newly designed front hub failures previously which caused it to drop out of contention, was out after 211 laps due to accident damage (Kinnunen and Siffert had switched cars; Siffert was now driving with Rodriguez). Then, Andretti brought the leading car in with gearbox problems. Although Merzario took the car back out again in the lead, the second-placed #15 Rodriguez/Siffert Porsche 917K was coming back after being 12 laps down for a while they were able to make up most of this deficit after the #19 Ferrari was in the pits. The Solar Productions Porsche 908/02 was in 3rd and the #21 Giunti/Vaccarella car was in 4th. And at 9:46 p.m. The #19 Ferrari was out of the race, which put the Rodriguez/Siffert Porsche 917K in the lead and the McQueen/Revson car was in 2nd.

With 30 minutes remaining, one car still running and desperate for an overall victory, Ferrari team manager Mauro Forghieri decided to replace Giunti with the faster and more experienced Andretti in the #21 car. Although the #21 car was a lap behind; Andretti went out, and pushed very hard; unlapped himself and was making up time quickly on Siffert and Revson. But then all of a sudden, Siffert brought the #15 Gulf-Porsche 917K into the pits with front hub failure, the same problems which had stricken its sister car. This long pitstop allowed the Solar Productions Porsche 908/02 to take 1st- but Andretti had managed to pass Revson and take the lead back. But all of a sudden Andretti brought the car back into the pits for fuel- and the McQueen/Revson Porsche took the lead once again. But Andretti was not about to give up so easily – with only 1 lap to go he stormed out of the pits and chased down Revson, and at the end of the 5.2-mile lap Andretti crossed the line first, with Revson second (who managed to score a 3-liter class win), Masten Gregory in the #33 Alfa was third and the #15 Gulf-Porsche was fourth. Of the 68 cars that started the race, the brutal Sebring circuit managed to whittle the field down to 28 cars.

Official results

Pos Class No Team Drivers Chassis Engine Laps 1 S5.0 21 SpA Ferrari SEFAC Ignazio Giunti Nino Vaccarella Mario Andretti Ferrari 512 S Ferrari 5.0L V12 248 2 P3.0 48 Solar Productions Steve McQueen Peter Revson Porsche 908/02 Porsche 3.0L Flat-8 248 3 P3.0 33 Autodelta SpA Toine Hezemans Masten Gregory Alfa Romeo T33/3 Alfa Romeo 3.0L V8 247 4 S5.0 15 J. W. Automotive Engineering Pedro Rodriguez Leo Kinnunen Jo Siffert Porsche 917K Porsche 4.5L Flat-12 244 5 P3.0 34 Equipe Matra-Simca Henri Pescarolo Johnny Servoz-Gavin Matra-Simca MS650 Matra 3.0L V12 242 6 P3.0 22 North American Racing Team (NART) Mike Parkes Chuck Parsons Ferrari 312 P Coupe Ferrari 3.0L V12 240 7 P3.0 46 Martini International Gerhard Koch Gérard Larrousse Richard Attwood Porsche 908/02 Porsche 3.0L Flat-8 236 8 P3.0 31 Autodelta SpA Piers Courage Andrea de Adamich Alfa Romeo T33/3 Alfa Romeo 3.0L V8 231 9 P3.0 32 Autodelta SpA Rolf Stommelen Nanni Galli Alfa Romeo T33/3 Alfa Romeo 3.0L V8 230 10 GT+5.0 1 Troy Promotions, Inc. Tony DeLorenzo Dick Lang Chevrolet Corvette Chevrolet 7.0L V8 219 11 GT+5.0 3 Bob Johnson Bob Johnson Robert R. Johnson Jim Greendyke Chevrolet Corvette Chevrolet 7.0L V8 214 12 P3.0 35 Equipe Matra-Simca Dan Gurney François Cevert Matra-Simca MS650 Matra 3.0L V12 213 13 GT2.0 53 Brumos Porsche-Audi Peter Gregg Pete Harrison Porsche 911T Porsche 2.0L Flat-6 205 14 T5.0 40 Takondo Racing Vince Gimondo Chuck Dietrich Chevrolet Camaro Chevrolet 5.0L V8 203 15 GT2.0 52 Jacques Duval Jacques Duval Bob Bailey George Nicolas Porsche 911T Porsche 2.0L Flat-6 201 16 T5.0 39 Bob Mitchell Bob Mitchell Charlie Kemp Chevrolet Camaro Chevrolet 5.0L V8 191 17 GT+5.0 9 Mamie Reynolds Gregory Bob Grossman Don Yenko Chevrolet Camaro Chevrolet 7.0L V8 189 18 T5.0 95 Bruce Behrens Racing John Tremblay Bill McDill Chevrolet Camaro Chevrolet 5.0L V8 187 19 P2.0 73 Ring Free Oil Racing Janet Guthrie Rosemary Smith Judy Kondratiff Austin-Healey Sprite BMC 1.3L I4 187 20 GT+5.0 2 Troy-Promotions, Inc. Jerry Thompson John Mahler Chevrolet Corvette Chevrolet 7.0L V8 187 21 T5.0 91 Flem-Car Enterprises Jim Corwin Donna Mae Mims Chevrolet Camaro Chevrolet 5.0L V8 184 22 T5.0 92 Preston Hood John Elliott Don Gwynne Jr. Chevrolet Camaro Chevrolet 5.0L V8 182 23 T2.0 50 Nationwide Food Brokers Mike Rahal Hugh Wise Werner Frank Porsche 906 Porsche 1.9L Flat-6 181 24 T5.0 37 Collins-Wilson Racing Vincent P. Collins Larry Wilson Ford Mustang Ford 4.7L V8 175 25 GT2.0 57 Waldron Motors John Belpreche Jim Gammon Ray Mummery MGB BMC 1.8L I4 175 26 GT2.0 58 Waldron Motors Ben Scott Dave Houser Lowell Lanier MGB BMC 1.8L I4 169 27 T5.0 18 Paul Pettey Paul Pettey Roy Hallquist Ford Mustang Ford 4.7L V8 162 28 T2.0 80 Texas Speed Museum Rod Kennedy Mike Tillson Robert Samm Lancia Fulvia HF Lancia 1.3L V4 157 29NC P2.0 54 Automobiles of Italy Anatoly Artunoff Bill Pryor Abarth 2000SP Abarth 2.0L I4 166 30NC S3.0 51 Porsche-Audi Stephen Behr Merv Rosen Porsche 906 Porsche 1.9L Flat-6 158 31NC S3.0 63 Carlos Fabre Carlos Fabre Pepe Aguilar Chevron B8 BMW 1.9L I4 32NC S5.0 26 Randy's Auto Body Shop Bobby Brown Gregg Young Robin Ormes Lola T70 Mk.3B Chevrolet 5.0L V8 114 33NC T2.0 84 HCAS Walter Brown Joe Marcus Jim R. Sandman BMW 2002 BMW 2.0L I4 105

Did Not Finish