The production was staffed by an Italian crew because of former Chicago Mayor Richard J. Daley denying Hollywood production staff from filming within the city.
Isaac Hayes' instrumental "Hung Up on My Baby" is heard in the film twice - once in Lee's apartment, and during the final showdown with Snake. This instrumental piece has been sampled by Geto Boys for their hit single "Mind Playing Trick on Me" in 1991.
The title was never Two Tough Guys or Three Tough Guys, only Tough Guys. The 3 title was to add Isaac Hayes's fellow African American star Fred Williamson onto poster covers, which is misleading since Italian actor Lino Ventura is the main character with Hayes his co-star and Williamson with a very small role.
Italian censorship visa # 64625 delivered on 16 May 1974.