Old question on power steering. I can't remember what years Chevy power assist cylinder and valve component's are a practical bolt on to a 51 AD. I think that the info was seen on Stovebolt?
Chevy passenger car up through 64, Corvette up to about 80, and Mustang through 70. Dodge, International, and other pickups are also a source. The cylinder will anchor to the axle and the end of the ram rod will tie to the tie rod. The control valve is in the drag link and can be spliced into the factory manual drag link. There is not a "bolt on" unit but all brackets are easy to fab. Wait, I may have seen a set up where there is a clamp for the axle and another for the tie rod but not sure. I am sure I trust weld on ones more.