Daytona. During the 1970 season, the competition between the 5-liter sportscars of Porsche and Ferrari turned to the advantage of the Porsche 917. In 1971, Ferrari decided to give up any official effort with the 5-liter Ferrari 512. To prepare for the 1972 season, the new works prototype Ferrari 312PB was presented and engaged by the factory in several races. Roger Penske bought a used 512 M chassis that was dismantled and rebuilt. The car was specially tuned for long races receiving many unique features, among them were a large rear wing and aviation-inspired quick refueling system. The engine was tuned by CanAm V8 specialist Traco, and was probably able to deliver more than 600 hp (450 kW). As of today, it is unknown to what extent Penske's initiative was backed by Ferrari works. This 512M was painted in a blue and yellow livery and was sponsored by Sunoco and the Californian Ferrari dealer Kirk F. White. The car made the pole position for the 1971 24 Hours of Daytona and finished second despite an accident. For the 12 Hours of Sebring the "Sunoco" made the pole again but finished the race at the sixth position after making contact with Pedro Rodrigez's 917. Despite this misfortune, the car had proved to be a serious opponent for the 917. Not only this car was the fastest on track in Daytona and Sebring but it was also the car that had the shortest refueling time. The presence of the 512 M "Sunoco" forced Porsche to pursue his effort of research and development on the 917: The 917K short tail was modified, and the 917 LH aerodynamics received further improvements. New Magnesium chassis were developed. An entirely new car, the 917/20 was built as a test-bed for future CanAm parts and aerodynamic "low-drag" concepts. In Le Mans the "Sunoco" Ferrari was unable to break the 200 mph (320 km/h) barrier on the straight while the Porsche 917 LH were lightning-quick at speeds of over 240 mph (380 km/h). Mark Donohue qualified fourth anyway, which was the result of an aerodynamic configuration that favored downforce over drag, which helped in the twistier sections. The car did not have much luck in the race though. American Le Mans Series In April 2005, it was announced that Porsche would build an Automobile Club de l'Ouest (ACO) sanctioned LMP2 Class Prototype that would be entered by Penske