Why waste your time when with but a like effort you can swap in a superior rear axle that requires no "upgrades" to last and is a bolt in as well if you get one from right truck. I have a friend than has a 10 year old GMC 3500 van that towed a loaded enclosed trailer daily that can weight as much at 10000 lbs and his 9.5 is still going strong with well over 100 k on it now. Had it been a 10 bolt it would have been shot by now. I have a 89 4x4 Burb that I have had since new with 170k now that has towed some in its life and been cross country over a dozen times and its 10 bolt is getting worn and noisy now even though it has had regular servicing. Had it been a 9.5 (like it should have been) I have little doubt that it would still be quiet.

 

Maybe because a 14bolt is 700-1500 for a stock one and you can get the 10 bolt strong for a lot less