A suggestion. Use a new rotary compressor. The York compressor that came with the dealer installed AC in a 914 was a horsepower hog.
A very, very good suggestion indeed. I would recommend a sanden 5 series compressor, such as a SD508. As far as mounting one in, I made up come brackets that cleanly addpt the stock a/c mounting hardware to accept a sanden style compressor. The 508 wont require you to swap the pulley behind the fan either. You will just have to measure for the correct length of a/c belt. Easy enough.
I made two sets of brackets. Turns out I dont need one of the sets. If you want it, drop me a line. I wont be back home for another week, so I wont be able to get my hands on it quite soon. Otherwise, I could shoot some photos so you can get the idea of how to fab it yourself. Takes about 1.5 hrs of labor to make it look nice :-)
Take care,
Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance