I watched a movie called Shock today through Netflix. The movie came out around 1977, and it is very similar to Dario Argento's movies because of the time period, the dubbing of English, and the actress, Daria Nicolodi (who starred in several Dario Argento movies, dated and lived with him for a long time, and is the mother of his daughter, Asia Argento, who starred in XXX with Vin Diesel).
The movie wasn't the best, but you have to appreciate Mario Bava's (the director) style. The movie is also called Beyond The Door II. I think Dario Argento definitely blew this movie away in 1977 with his masterpiece, Suspiria, which was based on a story written by Daria Nicolodi.
Here are trailers for both films ...
The trailer for "Shock" is in Italian, but the version I watched was dubbed in English.