Never personally messed with the older ones like that but from what i know of the newer ones, frames are the same so you have what is needed to hang an axle. The cab itself is probably different in the hump area of the floor. That is the only major things to it that I know of but like I said I haven't worked on the older ones.
You'll need to chase up the front axle, Transfercase and the transmision if you want a married transfercase. Pluse a few more odd and ends here and there. Those old trucks are cool but if you dont have a welder and some time (read project). It might be too much.
If you don't have a welder you need to get one also a good grinder with those two things you can build dang near anything you want. It will be one heck of a project so budget plenty of time and money. Heres a quick list of things you will need to do. Weld on spring mounts run brake lines reinforce the frame lift the back(I think even if you use stock springs it would sit way high in the front) steering and probably build a new engine crossmember among other things. If that list scares you enlist someone who can help you and go for it. If it doesnt' scare you just go for it Good luck :rotfl: :rotfl:
I know a couple of people with 4x4 trucks that year, one is even a factory NAPCO conversion from 1965!!! :thumb: it's a pretty staight forward swap, can't remember if there is a difference in frame width between the years? Unless you already have the parts and tools to do this, it would be cheaper to buy an existing 4x4 toyota, or scout, or something like that. If you decide to do this let me know and I can get measurements and info for you :thumb: