This actually sounds pretty intriguing! From IMDb:
Roger Corman, noted producer/director, hired Jack Hill in 1964 to write and direct a horror film with the condition that he make liberal use of footage from "Operation Titian", a thriller Corman produced with Francis Ford Coppola (!) in Yugoslavia, but deemed unworthy of USA release. Hill was given actor William Campbell, Titian's star, and hired Lori Saunders (still using her original name of Linda Saunders, and soon Petticoat Junction-bound).
However, Corman didn't like the resulting film about a murderous sculptor possessed by the spirit of his ancestor, who was killed by a beautiful witch. So he shelved it for a year, bringing it out for director Stephanie Rothman to revise. Rothman turned the possessed sculptor into a vampire, shot extensive new footage (using a few members of the supporting cast) and---bingo!---"Blood Bath" was out in the theaters at last,
Might have to hunt this one out!
