The Stovebolt Site Forums The Shop Area General Truck Talk best a/c unit for 1958 Chev fleetside

I've not heard of Regis Engines. I've used both Vintage Air and Old Air products and am more of a fan of Old Air. I think their design is a little better...but either will be okay. The least expensive A/C only choice will be a complete underdash package (what we used to call a hang-down unit). You'd get the compressor, the mounting bracket, all hoses, the evaporator and condenser. Something like this, maybe: https://www.oldairproducts.com/product/cap-300-et-complete-package

If you want A/C, heat and defrost the cost will go up. Just a matter of what you need. Good luck!