It was produced by the "Yuppie Don" Michael Franzese, former capo of the Colombo crime family. It was allegedly a form of money laundering. Wether it was a passion for film or simply a business venture is unknown.
Bobbie Bresee revealed on the commentary of the BCI DVD release that she received some possessed voice coaching from Mercedes McCambridge (notable for the demonic voice in The Exorcist (1973)) while co-starring with her in "Charlie's Angels" (1976) Angels in Springtime.
The scleral contact lenses that Bobbie Bresee had to wear during some possessed scenes damaged her eyes. This damage resulted in her filming some scenes towards the beginning of the film without her eyesight.
On the DVD commentary, Bobbie Bresee revealed that producers set up bleachers for crew members to watch the filming of her sex scene.
The car driven by Oliver Farrell is a 1980 Bradley GTElectric. It was a fully electric motor, the main battery bank was made up of 16 6-volt batteries connected in series for a total of 96 volts. A switch inside the car allowed the driver to switch from 'Boost' mode, which delivered the full 96 volts to the motor for extra power, to 'Cruise' mode, which reduced motor voltage to 48 volts and extended the driving range.