77 full time front end HELP

[chevyman06]

Hey guys im confused here. I took my front end apart from my truck to do ball joints and what I found scared me. The needle bearing on the axle shaft was gone and the shaft was wore down so far the bearing wouldnt fit snuggly on the shaft. The front end was originally a full time but was converted to lock outs. Out of the three parts houses in town only1 could get me the outer axle shafts and they wanted like 80 bucks per axle. I thought there was a cheeper way I could go so I talked to a few people and I came up with an 83 half ton front end the guy thought the axles should swap. I gave 100 bucks for the 1/2 ton axle. It had automatic lockouts on it. I tore it down and got the axle shafts side by side. My axle had 1 groove for the snap ring on the out side of the splines. The 1/2ton had 2 grooves cut in it and the outer groove didnt line up with the 3/4ton groove. I thought easy fix so I took it to one of my buddies and he took it to work and machined that outer groove into it. Looked great. Ok now yesterday I got everything put back on and I went to put my 77 lockouts on and they slid in perfectly and i got the ring to fit on the hub but the snap ring groove on the shaft was about a 1/16 of an inch too far in. The guy has been a machinast for over 20 years so he knows what hes doing. He built my driveshaft and I have had no problems with it. So did I not get something assembled correctly or is an 83 1/2ton shaft shorter than a 3/4ton full time axle? are they different style lock outs from 77 to 83? I dont want to use the automatic lockouts. Guys im lost and I need some help I would like to get my truck back on the road this week cause its been laid up for almost a month now. thanks in advance.