1968 Dart. What is the purpose of the slot under the interior panel? It runs almost the full length of the lower door. It seems to make the door more flimsy. Is there a reason to try to de-couple the door interior and exterior?
so you can vacuum the crap out? - - - I have no idea... block it off permanently and see how it goes... kidding (sorta) ...it sure as hell wan't to save weight, even without glass they are pretty heavy.
I think when the press form those there is just not enough steel there to make all the ribs without distortion so it has to come from somewhere..... Or the expansion and contraction form temperature differentials of inside to outside may have been a cause for stress cracks on previous models....