Howdy all, I have a 2003 8.1 AV and I am starting to do mods, I just got a superchips programmer in and I wanna do intake and exhaust for my next mods, I dont wanna pay for a intake kit caus eI feel its a waste of money for a piece of plastic and a K&N cone so I'm gunn ado that same thing I did to my 200 ford F-350 7.3L diesel which is up to about 350hp and 700ft lbs of torque but anyways I just wanna put a piece of tubing where the stock air box is and put a cone filter there, does anyone know how big that factory opening is going into the airbox, looks kinda like 4"s but not to sure, though I might ask the pros! PS this is a kick ass board!