I'm putting a new A/C compressor on that came with a GM serpentine set-up on my 68 ZZ383. What I would like to know is where can I buy an R134 POA valve for it? I think I am going to have to buy the expansion valve as well. Any help would be greatly appreciated.

Expansion valve can be bought locally. POA can be bought from Vintage Air.

In fact, they may have a dummy POA if you looking to go for an orifice controlled compressor, meaning no POA & expansion valve.

Hopefully, others will give their suggestions.

Thanks. I went there to their catalog area but didn't see what I was looking for. Not sure if I overlooked it but I didn't see it.

also try out www.oldairproducts.com in Texas, they have tons of stuff old and new look.

I'm putting a new A/C compressor on that came with a GM serpentine set-up on my 68 ZZ383. What I would like to know is where can I buy an R134 POA valve for it? I think I am going to have to buy the expansion valve as well. Any help would be greatly appreciated.

The R12 expansion valve and POA valve will work fine with R134a
If both are in good shape, they are fine.
Performance will not suffer.
40* air from the Vents is 40* air from the vents.

The Drier does need changed, and any repairs made.