R134a pump that will fit an 89?

I am wondering if a late model compressor will bolt onto an 89 4.0? I am aware that you can conver from r12 to 134, but I also know that the pumps usually don't last as long being as they arent designed for the 134. I would like to swap in a newer pump so I can be assured that it won't crap out on me, and I really don't want to recharge the r12. Any help is appreciated!

Josh

i've been tossing around the idea of retrofitting my ac wit R134A, The kit is available, and I've used it on an 82 volvo, and a saturn with no problems. It has an oil charge in it, which will keep your compressor around. It's like $30