Converting factory AC to use R134a

[jimbosprint]

I would like to convert the factory AC system in my '72 to R134a so that in the long run it will be easier to service (and because it doesn't work right now). I understand the basics, but I'm learning as I go when it comes to this AC stuff so please explain like I have never heard of these parts. Thanks in advance!

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Questions:

Could I use the stock controls and evaporator, and change the rest of the system under the hood for R134a - compressor, condenser, fittings, hoses, drier?

I found in some research a recommendation to upgrade from the POA valve system to a orifice/accumulator type. I also read something about a switch that cycles the compressor on and off so the evaporator doesn't freeze. Can someone explain this?

Do I need a different expansion valve?

Is there a kit available for doing all this?

Is this a cost-effective way to upgrade the AC system that will also work well?