Continuity mistake: The cars change shape frequently during the movie. That depends on the fact that many scenes were filmed at real races, with real F-1 cars. The cars that the actors drove were, for the most part, disguised F-3 racers. There are at least three fake Ferraris, and they all look different. One of them seems to have been built to resemble a 1965 F-1, but altered to look like a 1966 model. The non-existent Yamura (built to resemble a Maclaren), that James Garner drives is actually two cars with different chassis, one of them seems to be used very little, except when it catches fire in a scene.
Continuity mistake: During the Belgium race it begins to rain. This is making it difficult for the drivers to see. The track announcer then states about Jean Pierre," He's only 2 laps away from his third consecutive win". At this point the view changes to a frontal shot of Jean Pierre coming over a rise and look, the track is completely dry, there is even sunshine. The shot switches back to an overhead shot and everything is wet again.