Heavier torsion bars are a good idea....just don't go to much oversize on them or it'll ride like a lumber wagon. You might consider front and rear sway bars too.
A good set of leaf springs are also a good idea.....along with an adjustable pinion snubber.
Pay real close attention to the front K-frame. Check the holes where the pin for the lower control arms mount and make sure none of the welds are breaking loose and/or the holes becoming egg shaped. Check ALL of the welds on the K-frame itself, some of these left the factory with some pretty poor welds. You might also consider boxing in the lower control arms and re-inforcing the tranny cross-member where the rear of the torsion bars fit in the hex sockets.