In addition to his directorial career, Hellman worked on several films in different capacities. He was the dialogue director for Corman's "The St. Valentine's Day Massacre" (1967), and second-unit director on Paul Verhoeven's "RoboCop" (1987). Hellman finished two pictures in post-production that were started by other directors who died after the movies were shot, the Muhammad Ali bio "The Greatest" (1977) (started by Tom Gries) and "Avalanche Express" (1979) (begun by Mark Robson). He shot extra footage for the television versions of "Ski Troop Attack" (1960), "Last Woman on Earth" (1960), "Creature from the Haunted Sea", and Sergio Leone's "A Fistful of Dollars" (1964). Among the movies on which Hellman served as editor are Corman's "The Wild Angels" (1966), Bob Rafelson's "Head" (1968), Sam Peckinpah's "The Killer Elite" (1975) and Jonathan Demme's "Fighting Mad" (1976). He also was an executive producer on Quentin Tarantino's debut feature "Reservoir Dogs" (1992).