Does anyone know where I can get the thin foam like material that insulates the airflow doors that are inside the A/C and heater core box? You know, the replacement for the fuzzy crap that shoots out of the vents on our old cars. 😜 Also any idea where to get the green foam material that acts as a gasket on various parts of the box?

 

It's not actually green... it just happens to discolor/probably mold over 25+ years
It is just open cell foam. You can probably find it online in peel-n-stick form or by the sheet and glue in place.
I used closed cell foam for gaskets on my hvac redo. The MD brand from lowes/home depot.

 

I used self stick closed cell foam to make the bellow for my 4th gen dash
a'c vent adapter. I'm not sure why the divert doors are covered in foam, My dash swap isn't final so, I've not cleaned them off yet.