I took my springs to a spring shop where they relined them, rearched them, and replaced the main spring. I told them I planned to reverse them so they put the fittings (bushings) for the thick bolt that goes in the front into the rear eyelet and bushings for the shackles into what used to be the front eyelet. I put the springs on and bolted in my my new 12 bolt posi with a couple of 1" lowering blocks and it is perfectly centered in the wheel wells!
While I was at it I replaced the bushings in the shackle mount. They were in there pretty good and after I couldn't drive the bushings out on my own I ground out the rivet heads with a 4" grinder, knocked the rivets out with a drift and hammer and took the mounts to the same spring shop= they pressed the old bushings out and new ones in, then I bolted them back into the frame with grade 8 bolts, nuts, flat washers and lock washers.
It turns out both of my rear main springs were cracked and had to be replaced.
If I had to do it all again, I might upgrade to thicker springs instead of 1 3/4 I'd go with 2 1/2"- I think Jim Carter sells a kit that includes the end mounts for around $450. I paid $400 for just the spring rearch- a little more for the new shacles and bolts... So, for the same money I could have gotten better springs=
