Mr Giant, is this a recon clutch and trans that you are putting in? If you've gone this far I'd be inclined to check the bushings and bearings, you don't want to be stripping this down again for a while. I'd use new tabs on the four little screws that hold the uni-joint yoke. Clean the threads well and use a little bit of red loctite on the bolts. As its a four speed it would also pay to remove the chassis crossmember that the reartrans mount bolts onto. It'll give you a lot more room to work, also means that the front of the torque tube can drop on the ground out of the way. What year of truck are we talking about here? Also if you haven't already got one, get a workshop manual. Yell out if you've got any more questions. Good luck.
Bob