[xracerbob]

Kramer-

Your on the right track- make sure the screen on the bottom side wont let any of the foam or filter material into the motor as this would obviously cause big problems. As for the actual filter material, The dirt track guys use some foam that is free flowing but still filters out the majority of the dirt. I did a quick search, but didn't find any that rang any bells. You would have to cut sections of it and sandwich between the screens, which shouldn't be too bad. I always thought the way to do it would be to put it into the stack without getting too close to the butterfly and you would have no hood clearance issues.

I'll keep looking and see what I find.