89 Sable AC Compressor Runs But Won't Cool

I have an 89 Sable with very low miles that I got from a relative. I swapped out the AC compressor with a good one from a 91 Taurus that I have. I recharged it and the compressor will run, but it will not cool. Anyone know why? Still undercharged a bit? Could the tube be clogged? What should the equalization pressure between high and low be for R-12?