What goes here?

[cwestra]

I am putting the components back in the interior and appear to be missing something.  On the picture below there is a significant gap between the heater box opening and the defroster vent.  I gotta believe something has to go there.  Any help would be appreciated.

[Moparal]

nothing really goes there. It gets people all the time. I put foam on mine tho

[dodj]

About the same amount of gap as mine. Tolerances were a little slack in the early seventies.

[jims challenger]

I used black duct tape...my gap was about that big too....

[cwestra]

Good to know.  Must work even with the gap.  I'll put something there to help it though.  Thanks, all.

[Alaskan_TA]

The gap draws in "cabin" air, so it mixes & evens out the temperature some.