I dont have no level concrete but I'm gonna use my deck its level. well I built it so that may be questionable haha just kidding its level. Gonna set some cinder blocks on the deck make sure its level all four ways set the old rear up on it take my measurements, then set the perches and the new rear match that angle and weld it. The hard part is gonna be carrying 2 rear ends up my steps on my deck haha! I may try and use the bottom step to save my back. It was a ***** getting it in the car by myself. I had to basically curl it over the leaf springs then go back and forth from one wheel to the other walking it forward all while holding the pinion up to keep it from digging in the ground. A freaking concrete floor and a floor jack sounds like heaven right now. You guess don't know how good you got it haha jk