oooh this is a good thread!!!!
it's true that '70s porn music kicks *ss.
in my experience , gay porn from the '70s and even the early '80 lifted much of its soundtrack music directly from vinyl without regard to copyright. i've even heard some great obscure disco cuts on vintage vhs tapes and then later stumbled upon the original records.
jacques morali, the producer of the village people, produced a gay porn movie and of course featured village people tracks throughout the film. there's even a great disco scene in it where the "actors" dance to "macho man." the title escapes me at the moment, but i'll figure it out if one of you doesn't beat me to it.