I completely rebuilt my 64 Chevy heater box. You will need a gasket kit at least and depending on what version of heater, control valves cables, etc. Mine required a new motor and a heater core (the old core leaked and ran down and ruined the motor) You can get these parts from a variety of restoration sources like Chevy Duty, #####, Early Classic, etc. They are inexpensive except for the core and motor) I sand blasted the sheet metal and powder coated them satin black. I had a little trouble with getting the exact heater core (they are different sizes for standard and deluxe so keep your old one until you get and compare to your new core. I had to send mine back.) I also ended up getting a special cable and control switch, mine is a standard unit, and relocated it in a more convenient location on the dash.
I’m about to post new pictures on my web page that outlines this very restoration, so keep checking back. Hope this helps.
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