According to lead actor/writer Richard Cardella, Crown International Pictures took over production and did very little post-production work. For example, many of the day-for-night scenes were not tinted.
During the drive through town, the movie marquee shows Killer Force (1976) and The Screaming Tiger (1972).
The car sent over the cliff was a 1965 or '66 AMC Marlin. The Marlin was built by American Motors Corp. from 1965-67.
The diving systems are rebreather rigs.
The sheriff's car deserves a ticket for faulty headlights. On the passenger side only the outer light works. On the driver's side only the inner light works.