Duster Cowl Hood??

Green1 has got it. Cool non turbulent air is the goal. Pressure gains from any ram effect are minimal at best until you're well into triple digit speeds.

It's generally excepted that the best pick up areas for intake air are at the base of the windshield (ducted from the plenum ala early 60's stock cars or 67-8 Z28 Camaros for example), in front of the car (65 Comet drag cars), or high up above the boundary layer (any number of cars with snorkle type hood scoops).

Maximizing the benefits of getting cool less turbulent intake air from from the base of the windshield means isolating that intake air all the way to the air cleaner from the underhood enviroment. Raising the entire center of the hood and extending it back over the cowl plenum on the 69 TransAm bound Camaro was probably less about styling than a way of minimizing intake tract turbulence and reducing the number of times the air turned getting to the air cleaner when drawing intake air from the base of the windshield. Putting the intake air ducting in the raised hood section also minimized underhood component interference and probably reduced costs too.

The Fox body Mustang crowd didn't have any qualms about adopting it for their own and cowl hoods on Mustangs probably out number the Corvettes and 1st gen Camaros sporting them by a large number.