During the sequence leading up to and including the explosion that kills Jed Moultrie and the Treasury agent, a dark-colored Mercury is seen parked at the gas pumps. It disappears briefly, only to reappear when Moultrie's car explodes.
During the opening chase between Doolin and the Treasury agents, the agents are driving a 1957 Chevrolet with a grill mounted emergency light. However, in one scene of the chase, the car changes to a 1957 Ford without the emergency light. (This Ford was part of another chase later in the movie.) The Chevrolet then reappears for the rest of the chase.
When Luke and Francie are sitting on a sofa, he has his right arm around her shoulder. In close-up her right hand is up, caressing his hand; after the cut to mid-shot, her right hand is holding a drink.
In the opening where Luke's '50-'51 Ford rolls over and is immediately able to drive off, you'll notice as it rolls it's obviously resting on its side.
Quick editing gives the impression that it landed on all four wheels.
When Lucas Doolan is being chased by Kogan's goons, he pulls a knob, spraying oil on the road. The goons go over the cliff and it is obvious the car going over the cliff is a different car. It does not even have a rear bumper or tail lights.
In the scene at the gas station where Jed Moultrie and the treasury agent are the victims of a car bomb planted by Kogan's men, there is a dark-colored early '50s Mercury parked at the gas pumps. The force of the explosion supposedly causes it to roll on it's side, however a heavy cable can be seen attached to the roof of the car and being used to pull it over. In fact, the Mercury starts to roll over slightly in advance of the explosion.
Thunder Road was filmed in and around Asheville, NC. However, some of the scenes take place in Memphis, TN. In one of the Memphis scenes, Robert Mitchum pays a visit to the mob boss (Kogan) who is trying to horn in on his family's moonshine business. Mitchum parks his car in front of a building with "Asheville Pharmacy" in clear lettering on the window.
Doolin drives a '51 ford with grille and trim changes to make it look like a ('50. Dialogue refers to it as a '50 when Moultry wishes to buy it.) The trunk handle, however, is the original '51. When he pulls the plunger to dump oil on the road, the camera looks down on the trunk of a '50.