Porsche 911 3.0 Carrera RSR

For the 1974 season, Porsche produced yet another evolution of the 911. Developed around the 3-litre RS homologation special, the 3-litre RSR which would become the most successful Group 4 car of its era. In its early years, the RSR swept all before it in IMSA, Trans Am and the FIA World Championship, production beginning in late 1973. Just 56 cars would be built.

They were equipped with Typ 911/75 engines featuring high-lift camshafts, Bosch slide injection and twin plug ignition. There was also a large capacity dry sump oil tank and dual megaphone exhaust from the 2.8 RSR. Displacement remained unchanged from the RS at 2992cc but the compression was upped from 9.8 to 10:3.1, the result having been 330bhp at 8000rpm.

Visually the 3-litre RSR was enhanced with special five-spoke centre-locking 15-inch wheels, these having been 10.5-inches wide at the front and a massive 14-inches at the back. Ultra-light glass-fibre panels were used for the ventilated wheel arch extensions, bumpers, front lid, engine cover and rear spoiler. Weighing in at a mere 900kg, the RSR was obviously a very quick car, speeds in excess of 170mph were possible and 0-60 took less than five seconds. For two years, the RSR swept all competition aside, providing Porsche with its most successful customer racing car.

Owing to their success, many of these 56 cars had very long racing careers, some were upgraded to 934 or 935 Spec and a great number were crashed or re-shelled. Very few cars still remain unmolested with so many have been re-shelled over the years, fewer still retain their original “matching-numbers” engines.