I tried searching here and the manual and I cant find the size Filter to order as a dropin. I am getting the AEM Dryflow if that matters, but I need to know the size to get. Any help is appreciated thanks.

 

i dont think it's a specific size, usually (at least with K&N) you order by part number. Pep-boys, autozone, or any stores like that should be able to look up the proper part number. Unless you have a CAI/SRI then it's most likely 3"