The steering gear is the same as all A, B, & E bodies, except 62-72 A-bodies (what they call "small sector shaft"). However, the spool valve on top has different fittings. My 65 A & C bodies have/had the same fittings. However, what really matters is matching the pump (or hoses). Indeed, my 65 Dart now has a later valve body since I had to match the later Federal pump I got, which was required to match the later small block water pump I decided to use to match the later radiator which was the only one I could get at the time. Nothing is simple when you start fooling with engine accessories. In 65, all bodies used the TRW pump. It looks like the later Federal pump, since both had the same round reservoir, but the rear bolts vary, so brackets don't interchange. Also, the TRW has an inverted flare port and large return tube while the Federal has an O-ring port and small return tube. I don't know about Saginaw (oblong reservoir) fittings. Anyway, you can use any combination as long as the pump fits the engine and pulleys and you can connect the hoses, though none of that is trivial, so best to stay 1965 style. Bouchillon and others sell brackets. Pulleys will be another learning experience. There seems to have been a bunch of setups, depending on pwr steering, AC, and varying year-year, and I have never seen info that documents them. Copy others and expect to buy some parts that don't work.
Another kink is that you will need a shorter steering column rod, at least that is true in A-body world. Indeed, people there will pay to trade columns since more want to change to manual steering to install a big block engine and/or headers. Those drag racing fools. When going to manual steering, they can use an adapter to makeup the missing length, but of course the reverse is not true.
