I haven't tried it yet... but it has been suggested to me to maybe try one of the R12 substitutes like:
http://www.es-refrigerants.com/produ.../3/default.asp
I don't remember the cost or part numbers, I bought all the parts about 7 or 8 months ago while I was in the process of my motor swap. I remember the only thing I had problems finding were the o-rings because the dealer had no part numbers for them. Instead they finally told me to bring in the old o-rings and they just gave me some that were the same size/thickness/etc...