I have herd a lot of different storys about ram air hoods and cowl hoods and the way I get it is that a cowl hood gets more air forced into it then a ram air hood .so I was wondering if it makes a differance on the height of the hood for air flow ,could somone tell me what the different sizes of cowl hood makes for different hp.engins.

a cowl hood works by directing high pressure air that
builds up at the base of the windsheild when the car is
at speed to the engine,ram air setups can also work
very well-due to the slope of the hood,the(modified)
CFI ram air works very well on my '82z

so witch one workes best for every day driving ????

The effect of ram air, even with a properly designed forward-facing scoop is almost not worth talking about until you get up around 100 MPH. How often do you tool around in a daily driver at those kinds of speeds? Plus the other stuff that can fly in there along with the air- dirt, bugs, road debris, etc.

Cold air, by comparison pays noticable dividends at any speed vs. sucking hot underhood air. I forget the math on it, but something like 1% for every 7*F drop in temperature, approximately. A 21* temp drop would be worth something around 9HP on a 300HP engine.

^^ I've heard 1% for every 10 degrees (according to Car Craft lol), but the point is reducing the air temperature makes a significant difference, considering how hot the engine bay can get