Engine swap mounts, bell housing adapter (if you wanna keep your manual tranny) and some time. Check out http://www.advanceadapters.com and http://www.northwestoffroad.com for the mounts. It is easier to swap in a ford though from my research due to the fact that the distributor is in the front of the engine.
Northwest has your mounts. $200 bucks Also headers for a 5.0/302/289 The fords a little more promising because its narrower (important for the steering shaft. But you might have to find a rear sump for the oil pan as most are either front sump or a fox bodys dual sump. +1 on distributor. Ive seen a chevota with a smashed out firewall for the distributor. But are you dead set on a GM motor? There isnt a good 5 speed to put behind a chevy thats cheap.
u could do a few other swaps...2jz, 1jz, the 1uz(all alum)..umm.. thats all i can think of off the top of my head.. whats the truck going to be used for?
looks good allenb did you have to modify the firewall for the distributor to have room and how bout the steering and could you tell me what all major modifications you had to make
my swap i put a 383stroker in my 87 2wd take a look, i made my own headers but bought the mounts from performance offroad...cost like 215 and they are really nice, i picked up a tranny mount too but it could easily be fabricated out of a piece of 1/2" plate