When Vince is under attack at the Drive-In, he gets into a 1957 Chevrolet Two-Ten Handyman. When the car crashes it's a 1962 Ford Falcon.
The story takes place in 1951, but Ruby's drive-in has a wide screen, two years before wide screens were being built.
Although the film is set in 1951, when the projectionist is killed, a 1970s can of A&W Root Beer falls off of a shelf, along with a red extension cord.
On the wall of the office at the drive-in is a poster for The Left Hand of God (1955), but the movie takes place in 1951.