The SC520 comes as supplied with 2 1/2" tall performance paper air filters elements but the scoop will accept 3" tall K&N E-3310 filter elements when used with standard blower center to center spacings of 8 9/16" to 8 5/8.

The scoop itself can accomodate Carb center to Center spacings up to 9 3/4" but once you get over about 8 3/4" center to center max you can only run a 2 1/16" tall filter in the front because by moving the front adapter further forward to accomodate the wider center to center you need to allow for the butterflies to open over the top of the front filter element.