Quoting Rausch:
Cowl indiction is just what it sounds like. The idea is to draw the intake charge from a high pressure area, where the hood meets the glass. The idea is that the high pressure zone created by the glass/hood/shape of the car (One of the highest drag points on a car, next to the frontal area) feeds the intake with higher pressure air. Not positive pressure mind you, but since the air is trying to go somewhere, drawing it into the engine is a bit easier.
Crappy explaination, but hopefully you get the idea.
Real popular with the late 80's early 90's mustang guys, among others. /ubbthreads/images/graemlins/smile.gif
Correct. One big missconception is that a cowl hood is to get air out of the engien bay. It isn't, it is to feed cool air to the engine because it is in a high pressure area. An easy way to see this is to tape a small piece of string to the cowl and see what it does while you are cruising. Spoiler... it will get pushed under the hood not toward the windsheild.
The vents in the EVO hoods and our JDM hoods are to exract heat from the engien bay. They are in a low pressure are and thus let heat our instead of force air in.
As for why new cars don't have them it because new cars don't come with carb on top of the motor. Most new cars have intakes at the front of the engine bay or have tube going to the frotn of an engine bay. Vents are there to allow cold air in because the front is also a high pressure zone, just like the lower windshield is. In reality it isn't just a muscle car thing, or have anythign to do with electronics, or an other wives tales, the engineers just moved the source of cool high pressure air from one place to another.
