From looking at pictures of truck engines, it looks like they use the same airbox for all engines (4.3L, 4.8L, 5.3L, all 6.0L & 8.1L) in the new body style stucks. Are the stock fender openings larger for the bigger engines? If not, it must flow a pretty good amount of air to support the HO 6.0L and the 8.1L engines. Sport Truck installed a supercharger and the company supplied a larger inlet for the top snorkel on the airbox. It was just like stock, it snapped into place and got it's air from the fender opening. The snorkel opening was larger and you made the fender opening larger also. That would be a good option, it looked stock but allowed the airbox to pull in more air. Just thinking! Sometimes it's good and somtimes it's bad .
Jim