This film was shot on the infamous Spahn Ranch, where Charles Manson and his "Family" congregated, during the late summer months of 1969 under its working title "A Time to Run."
The final film of Lon Chaney Jr.. His scenes for this film were completed in August of 1969, four months after completing his scenes for the film Dracula vs. Frankenstein (1971) in April of 1969. Dracula vs. Frankenstein was then released to theaters in December of 1971, six months after this film was released to theaters in June of 1971.
This film was shot in 1969, but was not released until 1971.
Lon Chaney Jr.'s hoarse and raspy voice in this film is due to the effects of his radiation treatments for throat cancer.
The first time since 1942 that Lon Chaney was actually billed in a film with the name 'Jr.' (and was top-billed in this, his final film).