I just bought a 1968 vintage Vashon Valkyrie "liquid fuel" rocket. The can tap for Freon-12 that came with the kit will not work on R134a cans, because the thread sizes on the outlet ports are different. I need an adapter that takes the large R134a threads and reduces down to the smaller R-12 threads for the original can tap, or an R134a can tap that has a 4mm (threaded) output port that will accept the short hose and basketball pump-style filler valve. I believe I can make this bird fly again, but I have to find a way to get the fuel into the rocket. I have scoured the internet without success. Any assistance or ideas on how I can overcome this obstacle will be GREATLY appreciated. All the R134a cans I have looked at have the same large size threads.