I remember someone used to sell a kit. The condenser is different in that it has a booster fan if I recall correctly. The evaporator and accumulator are available and are very common, basically a GM part that fits those 240s.

You are also going to have to source the appropriate wiring harness to run the system since the old system used an expansion valve.

Tony, since you've had a lot of experience with these systems, have you ever heard a groaning sound when it first starts up? I'm pretty sure it's not the compressor. Sounds like gas being released in the system? Definitely a groan and doesn't do it all the time. From inside the car it sounds like it's coming from the passenger side of the engine compartment - maybe the dryer? - expansion valve?

mine makes the noise too. I think its the expansion valve. Ill be tweaking mine as soon as we have some warm weather in Mo. You can still buy R12 on craigslist.

Messing with R12 is a total waste of time. You can get adequate cooling with R134a.

The groan is the flutter of the expansion valve.

You can swap everything except the condenser using the new accumulator and evaporator core. You are going to have to wire in a pressure cycling switch.

If it is the expansion valve, is that normal? Or does it need replacement? I've never heard that on a new system. And I am using R134A.

normal
 

I believe its normal. I do think the expansion valve needs to readjusted for r134a if I remember right. If its still the factory installed valve.

I don't believe thats an adjustment, rather, it should be replaced, as should the dryer/receiver can. When changing from R12 to R134a, you also need to flush out the system with a solvent to remove the old a/c oil, and then inject the correct amount of the R134a compatible oil.