The 1954-55 deluxe heater is called an Air Flow heater because it has the interior door/flap.
1. The ring/rubber-seal on the firewall (around the motor) is available from
Jim Carter.
2. That door is opening by a cable that usually runs under the dash to a mounting bracket to the left of the steering wheel. I do not know who sells this cable/knob assembly.
3. The 53-55 heater's defroster lever is just as you describe - it has a lever that you move with your hand. In earlier A-D years, the Fresh Air defroster was controlled by a cable similar to the cable used in 1953-55 for the interior Air Flow door (in #3, above).
Other deluxe heater gaskets/seals are available from Jim Carter
and from Chevs of the 40s .
