I rebuilt my whole ac system about 3 yrs ago with r12 and the system worked great. I am in the process of rebuilding my motor and painting my frame/firewall and will not use r12 this time the price is way to high. My question is for the ac guru's out there I have been told by several people to NOT use the poa valve setup with r134. I was told to use the later 73 and on orface tube style hose. This means I would have to cut my hose have a serviceable orface tube installed then connect the hose where the poa valve used to be is this correct? Or should I use the poa valve setup and just install r134, of course with new oil, evap, and system fully flushed.