 Early in the movie, Yves Montands helmet design is that of John  Surtees, who was driving for Ferrari at the beginning of the 1966  season. But Surtees left Ferrari for Cooper after two races, and  therefore footage of the real Ferrari with Surtees driving was no  longer available. Mike Parkes replaced him at Ferrari, and Montands  helmet design changes to that of Parkes for the remainder of the  movie. No reason is given in the movie for the change.