Rebuilt the front about 2 months ago, first thing I checked was the trunion preloads, they were loose and have been tightened. The wheel bearings have been re-re-torqued. The toe-in is 1/8in. The steering box has been tightened/adjusted as tight as it will go and is now back to around specs. Newer poly bushings in the front. Everything has been tightened.
The only other thing I think could be causing this is the negative arch in the springs.