Here is an old article from a Mopar mag where the conversion is explained with full detail, before some parts were available. I took pics of the article, althought I think missed one page.
Nowdays 4seasons offers correct replacements for dryer and expansion valve already set for R134 (got them), so don’t need to tune up or rebuild the existant ones. They already come with the correct green seals.
https://postimg.cc/gallery/ChwjbjBFor better performance also aluminum condensers are available with the CORRECT look to replace the factory iron one. (i got it too)
About the temp sensor cut off switch, you can get it build like the A body setup. A bodies compressors didn’t get the ECP valve, but a cycling cut off switch temp sensor inserted into the evaporator. For more info about this, read the master tech manual:
https://www.web.imperialclub.info/Repair/Lit/Master/295/cover.htm