Michael,
To help reduce the noise intake, I made an alloy air box. It is shaped to follow the contour of the sides of the chassis and picks up air through the heater opening. Lots of work to make the box, but looks and works well. Since the taper is to the front, no signs that the front cylinders are short on air.
Haven't dynoed before and after, but it sure worked to cut down the noise. Remember, San Diego stadium has 93 db @ 50 ft @ WOT.
Wayne