Can anyone tell me if anyone makes the thick rubber seal that goes between the heater box and the kick panel were it goes into the evaporator inside the right hand side of the car. I bought a heater seal kit for a 65 but this thick gasket wasnt in it. I tryed making one but when i wash the car it leaks around the heater box at the kick panel. This is were a non a/c car would have the vent there.

try using a mix of some gasket and silicone RTV, that is what I am going to try. I have the same problem.