It seems to be on pretty tight.... But I seem to notice that the power steering loosens up (to normal) when I'm turning as I accelerate. At idle (or near idle) it's really stiff. Almost like RPM's influence power steering pump function.

Maybe the belt is just so old that it's dried out and not gripping on so well. Definitely nothing I changed - I will try swapping with a spare.

Man, I love having a parts car, gives me so much opportunity to swap/tinker without buying a bunch of stuff that might not even be the problem.