When Jesus Franco decided to make a MACISTE movie, he wanted to cast Mark Forest in the title role but the Italian agent got Steve Forest signed for the role instead. Well you can image the phone calls after this mix up. (from a fan mag, 1986).
Continental Film Review CFR, covered the release of this movie in Sept, 1975, called AMAZON COUNTRY, IS A MAN'S COUNTRY. This was the first time that I every heard of this movie. I have only ever been able to find a copy in French.
The movie was filmed in Portugal.
Larry Anderson