The Daytona 24 Hours, held on the 2nd February 1969, was the debut race for the Roger Penske-entered T70 MkIIIB SL76/139. Driven by Mark Donohue and Chuck Parsons it was powered by a 5-litre Traco Chevrolet and looked stunning in royal blue with gold pin striping.
Donohue set the second fastest time in qualifying, 1m 52.7 (121.704 mph), putting the MkIIIb on the front of the grid next to the works 3-litre Porsche 908L of Vic Elford and Brian Redman.
It did not look very promising for the Penske car from the start of the race when fuel pick-up problems meant extra pit stops and the T70 was soon back in 7th behind 5 Porsches and a JW Automotive Ford GT40. However the Porsches soon began to suffer problems with their exhaust manifolds cracking on the rough surface of the Daytona banking and after 5 hours the Penske car was up to 5th although still troubled by having to stop for fuel every 20/21 laps.
The 200 lap mark saw the T70 now in fourth and the fuel problem was starting to improve however it looked as if all hope of a win was lost when a combination of a broken exhaust and bodywork damage following contact with the Porsche 908L of Attwood/Buzetta saw the Penske car stationary in the pits for nearly 80 minutes. As the clocks showed midnight the Penske car was now down in 11th, 44 laps behind the leaders.
Suddenly after another 5 hours of racing things began to change as two of the works Porsches and one of the JW GT40s retired and the T70 was now back to 5th although still many laps behind. Another Porsche retirement and a passing move on the AIR Patrick/Jordan T70 meant third place with only the leading JW GT40 of Ickx/Oliver and the Porsche 908L of Mitter/Schulz/Attwood ahead.
Next to go was the GT40 when Ickx retired with broken suspension and then incredibly the T70 was leading as the Porsche was out with a broken intermediate shaft to the camshaft, something that had plagued all the works cars. For the remaining nail-biting 5 hours the Penske car held on without any further problems to score a somewhat lucky, if very well deserved, victory.