Actors Abe Vigoda and Al Lettieri had recently appeared in Francis Ford Coppola's The Godfather (1972).
Uncredited actor Carlos Romero's slumped over/dead body adorns the poster.
Penultimate film produced by producer Hal B. Wallis whose final film in that capacity was around two years later with Rooster Cogburn (1975).
Location filming was conducted at the Harold Lloyd Estate in Beverly Hills in California, USA according to a review published in an edition of show-business trade-paper 'Variety'.
Second movie where Al Lettieri says that a Don is "slippin'" (as in, losing his edge). The first was about Marlon Brando in The Godfather, and here it's about Anthony Quinn (both Brando and Quinn starred in Viva Zapata decades earlier).