 Matra and Alfa Romeo were willing and able to compete, but only in selected seasons or events.Also, Ford's successful Formula 1 Cosworth-V8 engine was available for independent chassis builders, but vibrations made it unreliable for endurance racing.After having been beaten by the Porsche 917 in 1970, Ferrari abandoned further development of the Ferrari 512M, leaving the 512 to customer teams like Penske Racing and NART.