You have probably seen or heard about these swaps and want to keep your truck stockish. But a bunch of band aids may never work. Remember the rear end of a truck is light. That means that changes to the rear, many times, don't get "exercised" enough to effect the front as you have noticed. If Barry says it helped, then do it.
here is the swap info anyway:
http://67-72chevytrucks.com/vboard/s...d.php?t=366828