Revealing mistake: Towards the beginning of the movie Starsky and Hutch are driving the Torino and they get a call over the police radio. There is a shot of the car pulling a u-turn on a bridge from above. Look at the bottom of this shot, you can see tire marks where they practised the move before. (00:17:10)
Revealing mistake: Multiple times during the movie, specially during the chase scene towards the end, skid marks can be seen from previous takes which match the car's actions perfectly. (00:17:10)
Revealing mistake: When Huggy Bear meets Starsky and Hutch in the alley to supply information, there is a closeup on his face as he sits in his car and just before he leaves. In this shot, it is very obvious that the facial hair on his cheek is attached with a glue strip. (00:27:55)
Revealing mistake: On full screen format, as police chief is discussing Starsky's request for a new partner, immediately before he says "check this out," the number "500" appears on the lower right corner superimposed over the chief's left arm for one frame only. (01:04:55)
Answer: It's entirely possible, since they were not wearing their disguises at the prison, that they had already changed clothes, and therefore, could change vehicles.
Phoenix