Saw this movie between 1964-1966 at a drive-in. I was a toddler at the time but this one scene was of a man kneeling in front of a huge rock on a beach, beating his head against it. I seem to remember he gnashed his teeth and there was blood. He might have been a native. It definitely was a drama, maybe historical, and not a horror movie. I have always assumed it was Hawaii, but I guess it could have been any pacific island. I’m not too vague on the rest of the movie to completely rule out a war flick.
The movie was part of a double feature at a drive-in theater. A John Wayne western was the headliner.
It’s driven me crazy for decades. Ring any bells?