Sounds like a good plan...

BUT--I know you love the Yukon XL and all...but trying to make that bus fast is like Devin trying to find his dong--damn near impossible! I would get the rearend and dent fixed and then leave it alone... I only say this cause you have two other toys to mess with.

Leave the 5.3L in the Yukon XL and put the 6.0L in the 86--it will be better--trust me. Then once the 82 is gone and you have recouped some $$$ from that--pour some of it into the 86--to make it perform how you want it to. Quit messing with the SC crap and step up to LSX stuff!!!