You're talking classic film noir, you're talking Double Indemnity. It's got a Billy Wilder/James M. Cain screenplay, Edward G. Robinson's best role ever, Barbara Stanwyck in the worst blond wig ever, some snappy repartee, etc... but who cares about that stuff? This movie has some great cars! As in Fred MacMurray's '38 Dodge- definitely the car of choice for murdering insurance fraudsters- and of course the most anxiety-inducing "car won't start" scene in motion picture history, when the getaway Packard balks at leaving the murder scene. Unfortunately, this is the best excerpt I could find on YouTube; you get the Dodge but not the Packard.
Asploding for Effect: Magnum Force [internal]