I first saw this modification in Rob McGregor's Make it Handle thread (post 354)
http://67-72chevytrucks.com/vboard/s...=419251&page=9
I can't argue with it from what I've seen. As long as done correctly and correct clearance is maintained, its good. I was thinking about doing it myself. The upper would only have to be shimmed to correct camber (ok maybe a little to equalize caster). I think it is a good low buck way to dial in a better alignment. My only question, what effect does it have on the tie rod/steering arm arch when the arm is moved? I don't think it would make much difference but I am curious.