What I've heard about Duracool has not been good. I believe I'd run it by Vintage Air and see what they have to say. The 12/13 oz cans are selling for 8 to 12 bucks here. I just changed my '91 Dakota over to R-134 and it cost me about $60, but I also replaced the drier and metering valve since it had been a R-12 system.