Is there a seal between the defroster duct and heater box housing? 1971 GTO
 

Is there a seal between the defroster duct and heater box housing? 1971 GTO

On my car there is about a half inch gap between the duct and the heater box which effects the vent output. It is a non A/C car.

If I remember correctly, on my 72 with AC, there was a wide rubber band that went over that area.

No seal or gasket on heater equipped cars. That opening is how they came from the factory