S&S Super Stock Natural Cylinder Head Kit for Harley Davidson 1984-99 Evo Big Twin with 3.5 in. bore
High flowing ports and a specially shaped combustion chamber and contoured piston dome are what make these heads produce power. The increased "squish" area of this design sets up a controlled turbulence in the combustion chamber. That turbulence improves flame travel for a more efficient burn and reduced detonation. Special Super Stock pistons are required.