The Green Helmet

Both Ronald Curram and Glyn Houston are dubbed.

In the real Mille Miglia, the cars were numbered with three-digit numbers across their hoods, representing the times they started the race. In some of the film's Mille Miglia sequences the cars are numbered correctly, but in others they have different two-digit black numbers in white circles on the sides and back, the way cars would be numbered in a closed-track race instead of an open-road race like the Mille Miglia.