Muddy and Bigeddie, as far as the stock box goes, look at the rubber seal when you open the hood that sits right at the front of the engine compartment, just in front of where the air intake is. cut that. I keep the piece I cut out to insert back in when going on trails. Then, look at the hood. on the newer Broncos, I "expanded" the hole that was already there, and then drilled a bunch of small holes on the inner hood metal that faces directly at the air intake opening. You will probably need a pic of this, kinda hard to explain. Now, if you really want more "ram air effect", I had fashioned a "scoop" that pulled air from the top opening of the grille area that is meant to funnel air into/through the radiator.
The scoop idea below the bumper would mean having to dismantle it every time you want to go offroad.
The scoop idea below the bumper would mean having to dismantle it every time you want to go offroad.
