1976 Dart power steering - “ratcheting”

My Barracuda did that once.
It had a Federal pump on it.
I switched to a Saginaw and it was gone and in 20 odd years has not come back.
I took the Federal pump apart to see if I could learn something, but it looked perfect inside.
My thought was the the pressure relief was faulty, but IDK, maybe yours has dirt in it, maybe the spring broke, IDK.
BUT
I'm pretty sure it ain't in the box .........
Maybe your BJs are tight requiring more pressure than the pump can keep up with. But I doubt it.
I could be wrong but I'm pretty sure it ain't the steering box.