The Sanden/Sankyo line of air conditioner compressors are recognized as
great alternatives to the old York ones. They have less drag, run smoother,
and operate at a higher efficiency ratio.
You can find them for about $50 in junk yards or used parts places. They run
about $135 refurbished and up to $175 new (depends upon where you buy).

I've designed and built an aluminum adapter to mount a Sanden (508) to a
York bracket. In this specific case, in my Volvo.
I checked the adapter up against a York mount out of my Vanagon (as it has
it's engine out just now) and it appears it would work there too.

I made a web page that describes the adapter, with pix and diagram. It's
about the Volvo bracket and was originally made available to my Volvo group.
As it may work in the Vanagon (I've not tried it yet, but will soon) I
thought y'all might like to take a look:

http://users.aol.com/pschiemer/PaulsAdapterPage.html

In the very least it might pique your interest to upgrade your compressor
using this example as a guide.  It's free, of course (but you'll have to
make it yourself, or have it made for you.)
Once I do the actual work in my Vanagon I'll post the results here for y'all.