Despite the fact that the Blacktop head features a extra open combustion chamber (see “Head combustion- chambers”) it nonetheless has a greater static compression ratio (see “compression ratio”), this is only due to the piston structure. The Silvertop piston features a very smaller dome with two deeply angled exhaust flycuts, https://codynvcxt.blogmazing.com/30719612/the-greatest-guide-to-toyota-4age-for-sale