I just completed an a/c install in my 85 bj70. I used a hot rod air kit with their compressor, fabbed a bracket out of a factory 70 ac compressor bracket and a universal one from hot rod air. If you do this plan on 2 weeks as it requires alot of fab work and time. The fenders come off, the dash gets yanked and you start from scratch with a new climate control system. I thoroughly researched this issue and hot rod air proved to be the most affordable and practical solution. Check out
www.hotrodair.com. I am going to do a write up on this soon