Why would you want to change to the 3 speed from a 4 speed?
If you want an OD transmission go for at least a floor shifted one, then you can stay away from the troublesome column shifter and linkage. How about a T5?
Another option may be a faster rear axle gear and keep the 4 speed you have now, you can probably get the same overall results you are looking for.
If you must swap to the 3 on the tree then it sounds like you know what to look for, and what the issues may be, I bet you figure it out as you go. You will most likely end up in a junk yard puling all the goodies you need from a 3 speed equipped truck, seeing one together and having the parts available should answer a few more of your questions.
Good luck,
Grigg
