craftomatic,
the shorter isn't necessarily better. What you want is a clean flow of air. A stock rubber boot that most cars and truck use aren't smooth on the inside. And most stock air filters are restrictive. I to mod. the air box. I tried two things. I first closed one side and did as you did. I cut open some of the ports, an drove it for half a tank of gas. Then I closed that side and covered all but one port closest to the manifold and ran it the rest. My results weren't what I thought they were going to be. Actually the single port was putting out more power, and faster acceleration. This is when I learned more isn't better. It's the effecient air that is better. Oh ya and the paint I'm using can handle up to 1500 deg. I'm good freinds with my old science teacher from high school who got his masters in aerodynamics, and he gave me a lot of very helpful hints, that he learned while working at NASA.