the problem im having with it is i HATE the way it sits going down the road.I can never get the alignment rite and when it does it doesnt stay.I only got a 4" lift with 32s.I got a d30 sitting in my yard and figured it would be easier.
A D30 certainly would be likely to fix that issue, although is the strength penalty worth it? You'll be taking a double-whammy if it's a pre-'95 D30 with the small 260X axle u-joints too. Lastly, the D30's cartridge-bearing design is inferior to the D35's serviceable wheel bearing setup with locking hubs.
My guess is you don't have a long enough pitman arm with your lift to put your steering linkage back down flat (or inline with the TTB beams). Bad steering geometry is the #1 reason for alignment issues on TTB suspensions, and unfortunately the suspension industry doesn't seem to give a sh!t about it as they just keep right on selling lift kits with this problem.
The Skyjacker pt# FA600 pitman arm is the ONLY arm out there that offers a true 4" of drop, all the rest are more like a 2" drop. I'm betting this would solve your issue of tire wear just as well as swapping the whole thing would.
Also check that the ride height is correct on your suspension, as this would affect the alignment as well (the axle beam pivot bolts should be at the
same height to no more than 2" higher than the wheel hub centerline (1" higher being ideal)). Washers, or a spacer under the bottom coil seats can be used to adjust the height if needed.
Hopefully that will help, and if you still would rather swap, like some of the others have said, info on it should be easy to find with the Search engine here (the link Maverick posted would likely be among the 1st search hits to come up)