Both cars were built by the director. The Roadrunner featured a fake blower. The yellow Mustang's body kit was actually made of 2x6 carved and fiber-glassed. Only the hood was purchased from the car.
The project was filmed in five days with one pickup day.
The "helicopter shots" were actually done by strapping the cinematographer to a moving train and driving alongside.
In the original script, only the Mustang was suppose to go down the cliff. But it got stuck on a rock so both cars had to be sent down.