For 1972, the 5000 cc Group 5 Sports Car category was discontinued, and the 917 and its main rival, the Ferrari 512, became obsolete. In the 3000cc category, now renamed Group 5 Sports Cars, Porsche's main advantage was their low weight, as the engine was underpowered with . The new rules required a much higher weight () than Porsche could achieve (well under ), giving the advantage to Ferrari 312PB, Alfa Romeo T33TT and Matra with their more powerful F1-derived engines that had or more even in endurance trim.