The still left flywheel pictured is the earlier Silvertop design although the best is the lightened Blacktop. Though the Blacktop head contains a far more open combustion chamber (see “Head combustion- chambers”) it still has an increased static compression ratio (see “compression ratio”), this is solely because of the piston https://4age20vitbs13456.blogzag.com/83101694/the-greatest-guide-to-4age-20v-itbs