not to be confused with the 1971 Jesus Franco film Dracula Contra Frankenstein....
A mad scientist J. Carrol Naish descended from the original Dr. Frankenstein takes to murdering young women for experimentation in hopes of reviving his ancestors creation, with help from his mute assistant Groton Lon Chaney, Jr.. Dracula played by Roger Engel under the pseudonym Zandor Vorkov comes to the scientist promising to revive Frankensteins monster in return for a serum which will grant him immortality.This was Lon Chaney, Jr.s final horror film role and J. Carrol Naishs last film. Chaney filmed his part in mid1969 when the film was titled Blood Seekers. Naish filmed additional footage in 1970 when Dracula and the Frankenstein Monster were added to the story in his confrontation scene with Dracula, he appears noticeably older. Director Adamsons wife, Regina Carrol, appears in the film as one of the people who discover the two title monsters. The film was released on DVD by Troma Entertainment. ........
Source: Wikipedia