1966 Dart GT-it begins

Like the a/c vents at the end of the dash , but you well find you’ll want at least two in the center also .
I get your closing the outside cowl vent for the clean look and to block off the inside ventilation. I would have kept them for the nice days when you don’t need a/c .

Did you know that the cowl inlet is in a high pressure area and makes a great source for cold air induction to the engine just by creating a duct to the air filter from the plenum . Of course you’d want to use a dual snorkel air cleaner but turned around toward the cowl for a short run to two ports from the plenum .

NASCAR has been doing this forever .