Zero to Sixty (1978)
A middle-aged divorced man (Darren McGavin) becomes partners with a 16-year-old girl and must repossess a Mafia car with a corpse.Three Stooges meets Repo Man with a hint of underage sex. Cringe-worthy. Not sure how this was legal but hey it was the 70s. Features sexy Joan Collins who drives a Trans Am...of course.
Thomas Mossman commented
It's worth pointing that the 16-year-old girl is played by Denise Nickerson (Violet Beauregard from Willy Wonka and the Chocolate Factory).