Thanks Skyman! Yes in fact you could get a similar set-up for the '67 Z-28's that had a duct back to the slotted vents on the cowl.
I'm sure they have worked hard on airflow managment and aerodymanics and would think arbitrarily cutting open holes in things would most likely do more harm than good IMO. And sorry my post above was soooo long!
I'll correct myself! Should be HIGH pressure area at the base of the windshield also.