Going to swap the 66 1/2 ton rear end in on my 52 3600. From what I'm seeing on LMC and the shop manual, there aren't any spring perches. However, the PO had tried to flip the rear to lower it and had welded perches on the under side. I still have the original anchor plates and look as if they will fit on the 66 as well since both rear ends measure 3" around. So my question is: will I need to buy some perches and weld them on or not?