The Ferrari Formula 1s in Grand Prix were either true 1966 Ferraris or shells placed on another F1 chassis, BRM I think, for the actors to drive. If you look closely, Yves Montand did some of his own driving and the front end looked a bit different than the Ferraris in the actual racing sequences. You should try to get the VHS or DVD for your collection. The director, John Frankenheimer, did an outstanding job for which he won an Academy Award. The widescreen version coupled with the Dolby sound provides an experience you'll not forget. The racing scenes were well-filmed both from stationary ground cameras and from helicopters. The onboard cameras let you know what it's like to drive an F1. I originally saw the film in the theater when it was first released. In Cinerama and an early version of surround sound.