Chassis Number: 9114600085
In 1973, Roger Penske created a racing series called the International Race of Champions, or IROC. Equally ambitious and unique in concept, the IROC series aimed to place the world’s best racing drivers in identical cars to compete against each other over several rounds at leading U.S. venues. To compete in his special racing series, Penske contracted 12 of the top drivers from the four main branches of racing: Formula One, SCCA, USAC and NASCAR.
While deciding on a car to serve as the basis for the IROC series, Penske consulted with his star driver, Mark Donohue. His answer was unequivocal: If Penske wanted a strong, fast, reliable and consistent racing car, the only reasonable choice was a Porsche. Donohue, who had driven an RSR in late 1972, suggested that Penske contact the Porsche factory and order a run of the latest racing 911s. Penske followed Donohue’s advice, and, at Penske’s request, Porsche built 15 examples of the 911 Carrera RSR for the IROC series. Built to identical specifications, the brightly painted IROC RSRs were essentially hybrids of the 1973 2.8 RSR model and the new-for-1974 3.0 RSR. Mechanically, the engine was similar to that of the 3.0 RSR, though high-butterfly mechanical fuel injection was used instead of the more-exotic slide-valve injection found on the standard 3.0 cars.
