Can someone tell me how much Freon R12 is used in a 1967 Jaguar 420 A/C system? I may try to revive my existing factory A/C if I can locate a new receiver/dryer and new hoses. I am familiar with R134 conversions and have done a couple on older Mustangs. What I want to know is the TOTAL WEIGHT of R 12 that was used. Thanks Pete