Years back,my friend,Ron,swapped stock '49 Studebaker axles from his 3/4-ton. He was converting it to 4X4,so he opted to swap '74 I.H.C. 3/4-ton springs,axles and transfer-case. Point here is that the guy who welded the spring perches to the frame,didn't get a correct measurement on the axles! The springs had at least a 1/2-inch-bow,to the outside of the frame. He must've had a heck of a time,trying to get those springs in the perches! Every time that truck hit a bump,that thing would "jump",but you wouldn't know from one time to the next,just how it would react! It was a wild ride,to say the least. Now,either we do the operations ourselves,or take it to a TRUSTED pro. Just 'cuz somebody says they can do something,is no guarantee that they can. Just be on the safe side,and check,and double-check your measurements!