Restore factory ac or go aftermarket

The only reason I would EVER stick with a factory system would be in the case of my 75 F250. It literally has every single piece of the system there and still has R-12 in the system. It has some electrical issues from the blower motor locking up years ago that I need to fix and then it will probably cool AS IS. Everything in the HVAC box works. Even the defrost. The blower motor just does not run.

If you are missing items as you say, then it would be crazy not to upgrade. Those little Sanden compressors are very nice, compact and light and they cool great. I think it's a no brainer. You sound like me though and don't have a pile to throw at it all at once. If you have a local AC shop, try going by there and feeling them out. The one we have here will work with you on stuff real good. I have had friends who bought one or two pieces at a time from them almost as cheap as an online kit and they have the local, professional advice to help if they need it.