Re: Old vs New
Keep your inside controls and underhood suitcase.
If you don't want to spring for a modern low HP draw compressor, just get a replacement A-6 and convert it to R-134a compatible oil. You will have to swap your existing hoses out for barrier hose in order to run R-134a, but if you still have the original hoses, it's probably past time.
I have a '67 with AC in FL and enjoying the car in summer requires good AC. I have a hybrid system using R-134a, a reconfigured POA, new parallel type condenser, new barrier hoses and the Sanden compressor. Works just fine.
You don't need the POA eliminator, just dissassemble your top hose (after safely discharging your system with a freon recovery system), look into the fat end of the POA for the small nut (5/32) and screw it out (CCW) a 1/4 turn. The POA eliminator cycles the compressor and puts extra wear on the clutch plus it costs $100.