Difference in power steering pumps?

Pressure port location is different - Saginaw comes out the back, Federal/TRW comes out the side. I know a clearance issue on 70-72 A k-members necessitated the Federal pump. That said the internals are different and the two pumps have different bracket set-ups. Saginaws are readily available and you could get on Chryslers + GMs through the 80s that are the same basic pump with minor variations that shouldn't affect compatibility. Good luck finding a rebuilt Federal.