Axle Swap Questions

[Brningdawn]

I have a 1992 GMC K1500. 5.7 with 700r4, 10 bolt rear, 3.42 gears. All stock. This is my project truck, but I've never done this before. I've been trying to figure it all out.

I am planning to either beef up the 350 a bunch or I'm going to drop in a lq4 motor with a new transmission. I know all the extra power over will wipe out my rear end and I want different gears anyway.

The local pullapart has a 1989 Chevy K2500. It has a 5.7 as well. I believe a TH400 transmission. What I am after is the axles, both from and back. I've been doing a lot of searching, but I just want to make sure. The truck has a 14 bolt, and I assume semi float, rear end. I'm also assuming it has at least 3.73 gears given that it's a 3/4 ton. It's also a 3/4 ton with 6 lug, not 8. Based on what I've read it should be a straight swap. Can anyone confirm this?

My truck is a short bed and the donor is long bed. If the rear axle will swap right in, do I need to grab the leaf springs with it?

On the front, will it bolt up with my existing front end? Can I just disconnect the mounts and unbolt the cv half shaft or do I need it all? What about control arms and stuff like that? I'm not sure what front it has, but I know that the gears will match the back so that's I'm really concerned with.

Should I pull the TH400 with it since it's only $75 extra dollars? Drive shaft? Mounts? Etc?