The shell we are rebuilding ws originally an AC car. Beings none of the components for the AC are there I just want to switch the box to a non-AC box. Does anyone know what other vehicles used the same inner heater box? Thanks.

The hole in the firewall is different between w & w/o ac. One solution is to snatch a hunk of a w/o-ac firewall and graft it onto the car.

The heater box in the Ames GTO catalog listed for 66-67 looks an awful lot like the one in my 67 bird. So maybe 66-67 GM A-bodies share the 67 bird box.