Big P p p p p pete Geoghegan's Mustang had a beautiful John Shepperd crafted aluminium shroud attached to the bonnet which kept the incoming cold air separated from the warm engine bay air.
I've seen some better photos but this is all I can find at the moment. I think it's enough to give you the idea.
Legendary 1967 GTA mustang racer-News & Reviews-Unique Cars
Jim Richards runs something similar on either the Falcon or the Javelin.
http://blog.hemmings.com/index.php/tag/shannons/