Peter, this isn't a step backwards, it's a blessing in disguise. The best thing for you to do is upgrade to a rotary compressor. The model that's usually recommended is a Sanden SD-508. All you need to install it in place of the old York is a York to Sanden adapter plate, which all A/C parts suppliers will have.
IPSCO has the adapter plates too. IPSCO also has an A/C idler pulley upgrade kit which makes setting belt tension a breeze.
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