911 RSR or IROC (Turbo) '74 and later

The RSR Story: The 911 RSR 3.0 (commonly called IROC RSR), or to be more precise, an RSR that was really more a combination of RS and RSR components and was specially built just for the IROC racing series. It was an inspired concept, putting twelve of the world’s premier race drivers into identical race cars and letting the flag fall! It was Roger Penske along with Les Richter and Mike Phelps who developed the first IROC challenge. Also, credit should probably be given to Mark Donohue for suggesting to Penske that Porsche’s RSR would be an ideal car for the racing series. According to Karl Ludvigsen (Porsche: “Excellence was Expected”), Donohue had tested an RSR prototype at Paul Ricard late in 1972 and was so impressed by the car’s manners and its apparent durability (Donohue was also confident that Porsche could prepare a fleet of closely matched cars) that he deemed the car ideal for the IROC series. The Drivers of the first race in 1974 were the reserved champions of motorsport: Bobby Allison, Mark Donohue, Emerson Fittipaldi, George Follmer, A.J. Foyt, Dennis Hulme, Gordon Johncock, Roger McCluskey, David Pearson, Richard Petty, Peter Revson, Bobby Unser. All of them title holders at the time. The IROC cars sported the narrower RS fenders, which allowed 9” front and 11” rear wheels with regular bolt-on rims rather than a full race setup. Carrera graphics were replaced by Porsche logos, and each car was painted a bright color for easier driver identification and better TV viewing. With the decline in interest in prototype racing and the 1974 demise of the CanAm series, suddenly production based cars such as the RSR were elevated to headline status and the factory went out of its way to assist customers.