Hmm 36's probably 4" Susp. 3"Body should get it. 6" susp 3" Body on the 38's. I used to run 36x12.50-16.5 Hummer Tires on my truck and I have like a 9" wide rim.
With 36's and 38's that 300 I6 and stock gearing will have a time trying to turn those puppies around. A 302 swap and some 4.10's would be fine I would think. Those axles probably will hold up if you are easy on her. you have a D44 TTB and 8.8 rear more than likely if that thing is stock.