Chevrolet Repair: GM ac compressor and more, gmc sierra, ac compressor

Question
1985 GMC Sierra PU.  "Compressor is bad, you should convert." was what the mechanic said.  Can't I still buy an AC compressor to replace the old one?  Conversion is $$$$$.  Another question: AT (700)is hard shifting and I want it fixed.  I was told a rebuild is as expensive as a new one, so buy a new one.  Whaaaaaa?  Any advice?

Answer
replacement is cheaper and i would go that way. as for the hard shifting, a rebuilt is as expeniseve as a new one?? HAHHAHAHAHAHAHAHAHAHAHA. get another opion, a rebuilt should be way cheaper than the new one.. more expensive  pardon me while i go laugh.