New guy here with a couple of questions

[Texengland]

I picked up an 82 K20 (350, 4spd) a few weeks ago and apart from some minor rust issues and a slightly smoking motor she is in good shape. I've wanted a truck of this model since I was a kid and now that I have it I plan on doing a full resto whil it is still my DD. I always go through and refresh fluids when I get a used vehicle and for this I was wondering what the best fluids and weights for the diff's, tranny and xfer case are? I was also wondering if any 350 short block can be built up and used in this model truck? Reason I ask is becuase I plan on looking for a good block at the junkyard and rebuilding it over the next year along side my Cherokee's 4.0. Thanks for the info and I'm sure i'll be back with more questions as the years go by.