Pls recommend source for full AC system for non-AC 1971 5.2 L Duster

I would use Classic Air again, but beware - they market this like it is all scienced out and all the problems are solved. This is absolutely not true - a "perfect fit kit" it is not. If you are reasonably skilled hot rodder who can do some light fabrication you can install the kit and address the inherent problems, just be prepared that this is the situation. It isn't a plug and play situation. They have slowly changed their set up over time, but you should look around on here and read through some of the accounts of the kind of work that it has taken to resolve design issues. The worst part is that when you find problems, 80% of the time the "techs" at Classic Auto Air are useless in helping you, and frankly give you that "I couldn't be bothered by your problems" vibe. You are more likely to find real practical solutions right here at FABO.

Whatever you do, DON'T buy the front pulley set up based on the use of a factory air crank pulley. PM me if you want to know, but their set up in 2023 resulted in a system that squealed like a pig every time the compressor kicked on. The folks who used the add on pulley groove set up that gives the belt more wrap around the pulleys and a separate belt for the compressor seem to have a lot fewer issues in this regard. Follow CAA's advice to mock up the system on a bench, power it up and make sure everything works as intended. After it is in the dash it's a pain to work on and the alternative is to take stuff all apart again.