The bulk of this film was shot in mid-1967 (shooting title "Operation M"), including all footage with Broderick Crawford, Scott Brady, Kent Taylor and John Carradine. Production finally wrapped in 1969 with biker footage featuring Robert Dix, whose name is only listed in the opening credits. Apparently, the addition of the cyclists was the only way the producers could get their picture released. This was one of seven completed features awaiting distribution when Al Adamson and Samuel M. Sherman formed their company, Independent-International Pictures Corp., beginning operations in 1969.