Chrysler 8 1/4

A 8.25 and shorter driveshaft is probably the least expensive swap while gaining some strength. The next least expensive is the Ford Explorer 8.8 with on side cut down and a 2nd donor axle added from the other side. That is as strong as a 8.75, and posi and disc brakes are usually included as part of the deal. A LBP 8.75 limited slip for Abody seems to end up over $1000. To get a Jeep axle worth it you probably would need at least a Dana 44 and they aren't cheap because lots of the Jeeps guys want them for their swaps, plus the width still isn't right anyway you'd be better off with an early-mid 60s B body 8.75.