While the Blacktop head features a much more open up combustion chamber (see “Head combustion- chambers”) it even now has a better static compression ratio (see “compression ratio”), this is only because of the piston design. The Silvertop piston incorporates a extremely compact dome with two deeply angled exhaust flycuts, https://4age-20v-itbs61343.blog2freedom.com/31339875/the-smart-trick-of-toyota-4a-ge-that-nobody-is-discussing