['63GENIII]

Id be looking at the later 4500. I think that the break point for the more modern one is either 94 or 95. Get the one with the square shift tower as opposed to the rounder one. IIRC, in addition to the more streetable 1st gear, they also have a syncro reverse (which is nice) and revised / updated shift forks that aren't prone to dragging as much as the earlier versions.

I had thought of coupling a 4500 to the 205 with one of the adapters out there. After much reading and searching, I found a '93 2wd 4500 for 700$ and a Dodge divorced 205 for under 200. Yes its a divorced set up and not as compact as a married unit but works flawlessly and was much cheaper than the married unit. Arguably it was way less $$.

One other thing to consider is the dreaded 5th gear nut failure. I could be wrong but 2wd transmissions are way less prone to this problem being that the 5th gear nut is on the outside of the trans and holds the rear yoke on (visible) unlike the married version which cannot be seen unless disassembled for inspection.

To be fair though, I usually hear about 5th gear problems when behind a Cummins for understandable reasons.

They are easy to build with a manual and a few special tools (really good snap ring pliers) a press and a grinder.

If you do buy used, be ABSOLUTELY sure that the correct Syntorque or approve equal was used. If you get one with regular gear oil in it, you will be missing some snycros. This sucks to find out on your first test run.