The voice heard on the other end of the phone, when Chase eavesdrops on a phone call to the police department, is that of Ken Curtis, who served as producer on this film. He is more famous for having played scruffy deputy Festus Hagen on Gunsmoke (1955).
Ken Knox, who plays disc jockey Horatio Alger "Steamroller" Smith, was a real disc jockey working at radio stations in Texas owned by Gordon McLendon, the uncredited executive producer of this film.
The "Gila Monster" is actually a Mexican Beaded Lizard.
This was one of two features produced by an independent company in Texas and meant for release as a double feature. The other feature was The Killer Shrews (1959). Unlike many such features produced in the South, these films received national distribution.
The car Chase drives was owned by a local farmer and drag racer named John Mulkey, who won the B Street Roadster class with it at the 1958 NHRA Nationals. It ran a small-block Chevy massaged to 302 cubic inches, and ran 105.5 mph in the quarter-mile. The car has gone through several owners and major changes over the years, but exists today.