What you want is an F210 model York compressor which is one of the most common a/c compressors you'll find in auto wrecking yards. That's what I used in my York system and it worked great, never a hiccup. The F210 is a ten cubic inch compressor and it can crank out 6-9 CFI with the engine just up off idle.
I paid $35 for mine from a local junkyard. They had 6-8 to choose from so I picked the best one by connecting one of the junkyard's old batteries to its solenoid wire, spinning it with my hand, and picking the one with the most suction and output.
I would contact Brad Kilby at ::Kilby Enterprises::
POSTE HASTE to get this mounting bracket because he is shutting that part of his business down. That mounting bracket is the key to turning this into a fairly simple project.
One more thing, look for a York where the two top manifolds are held on with two small bolts each. Some are, others make it nearly impossible to attach the in and out airhoses to. Brad has a bolt-on connector to replace the two ports (suction and output) that replaces both of them which makes connecting the hoses up easy.
Here are a few good links for you...
(alternative bracket to Brad's)
(to help identify an F210)
(another Brad Kilby website)