When Roy Fuchs approaches Rudy, Jeff and Jim as they are just finishing the burial of the Edsel with Luke in it, Jeff dumps a shovelful of mud on Roy's white shoe. When Roy walks away later, his shoes are both clean.
During Luke Fuch's last ride in the Chevy, he tears the shoulder of the driver's Castrol jacket, exposing a patch for his brother's used car lot, which later falls out of his hand as he dies on the floor of his dealership. When the driver hops out of the '57 and makes his escape, though, his Castrol jacket's shoulder is intact and un-ripped.
The Edsel mounted on the pole at Luke Fuchs' used car lot is a 1959 model. In a later scene where it is brought down from the pole (to orchestrate the "death" of Luke Fuchs) it is seen crashing into a power station. But the car so careening into the power station is actually a 1958 Edsel. You can also tell it's a 58 when they are loading Luke's body into the front passenger seat.
When Mickey and Luke Fuchs are on the 57 Chevy demolition ride, Mickey heads the wrong way on the street, playing chicken with two cars. In the approach shot showing Mickey driving towards the cars, we see two cars approaching him side by side with another car slightly to the rear of these. But when the view changes to a direct shot as the cars pass, this third car has disappeared.
during the opening scene, as the camera pans the Edsel mounted up on the post, you clearly see through the grill that the car has no engine. Later in the movie, dead Luke drives the car across the field and explodes it into the power station.
During the opening credits, Rudy puts a sign on the windshield of a car that says "LiKE NEW" with a dot over the "I". When he slides the sign over to hide a crack in the windshield the dot over the "I" is gone.
The scene in the bar where the Denver Broncos are playing the Kansas City Chiefs is actually an Arizona State University game. You can see the maroon and gold uniforms, the "Sun Devils" script in the end zone, and Sparky, the ASU mascot on the bar TV.
Jeff pulls up sharply next to the tow truck in front of the train, and proceeds to fiddle with the tilt tray controls to roll the car on the back off, yet the driver of the truck fails to react in any way.
When the judge measures the 1974 Mercury Montego, he says "You're two inches short." Jack Warden laughs and strikes the trunk lid, and the license plate drops, showing the gas cap. The gas cap on a 1974 Montego is really above the rear bumper, between the tail lights, behind a door.