Harley 4 valve heads7 Oct, 2016 in Head Hoggers tagged harley 4 valve heads / harley engine kits / Harley Performance / Head Hoggers by headhoggers (updated 2986 days ago) Just got a set of Harley 4 valve heads in with cylinders and Pistons. Let the R&D begin! Doing flow before and after. Should be fun. Will have some new stuff coming out for them