SinisterSix

Do you get any HP gains with a Ultra-Z Hood? so what kind of RWHP should you get?SLP say Gains of up to 10 to 15 additional horsepower are possible. but have any one really dynoed it? does it get more or less then the SS hood?

2000GTP

If you make a functional setup, you should get gains similar to a cold air intake setup.

Z28SORR

First off the 10-15fwhp is from a stock setup, on a ~290hp engine. And this comes from SLP's dyno test. If you already have a CAI, your not going to see any measurable improvement.
Theoretically, the Ultra-Z hood should be an improvement, very very small, over other CAI's because the inlets are in an almost perfect location.
There is almost NO ram effect until you get well over 80mph.
At 0.0mph, and 14.70psi, at standard atmosphere, you'll only increase by 0.1psi at 76.12mph, and only by 0.5psi at 152.36mph.
So that you get is from unobstructed flow of "cold" air.
The SS hood is not a very good design, but does function better than stock, because of it's relative height above the ground(cold air). It's in one of the worst area's, low pressure spot, and when they screwed up the flow by putting two baffles right after the opening.
P.S. This is for the 96-97 SS hood.