Hack Job AC conversion!

[Smallz72project]

My 86 K10 either was a non ac, or had a non ac cab swapped onto it at some point. Heater was not working and blower was only blowing around the passenger side end of the diverter (corner is broken not allowing it to seal). I found that they cut the firewall to accept AC but left the non ac hole there (it should be welded shut for it to work). This weekend I am going to disassemble the truck enough to cut out that part of the firewall and weld in new metal. The ac is not functional and is missing half the parts for it anyhow (all that's present is the underhood ac components on firewall, ac diverter box, and control unit), so I want to just go back to a regular heater as AC isn't vital for me in Montana. Shy of junk yards, where would I be able to find the non ac diverter box and the non ac blower pod for inside the engine bay?

Thanks in advance!