Here are some a/c part numbers and to get you started on a a/c sanden compressor 134a conversion, a/c install.
Porsche 914 a/c installation instructions, part# ZPW-805_914
available from AA
Custom bearer type hoses and exspansion valve avialable from
www.rayeveritt.com
great web site
York to Sanden compressor adapter available on ebay or
Bus depot part#2554
Receiver- dryer available from Proair LLC part# 05 000 072
or Bus depot part#477820193
belt Dayco Part#15475 11mmX1205mm