 The latter car was also used for all but two interior shots.Both 1971 Mustang Sportsroofs used in the film (neither car has been proven to be a Mach 1, as often assumed) were bought in 1971, but - as it was three years before Halicki could raise sufficient funds to start filming - each car was facelifted with 1973 grilles for the film.Both cars retain their 1971 front bumper and valance panels, as retrofitting the 1973 parts to the car would have required swapping the fenders as well.