We created a backing plate that perfectly mounts up to the Silvertop and Blacktop 4AG and lets the... Though the Blacktop head incorporates a more open up combustion chamber (see “Head combustion- chambers”) it however has a better static compression ratio (see “compression ratio”), this is purely due to piston https://blacktop20v4age45788.bloggerswise.com/47905245/what-does-4age-blacktop-engine-for-sale-mean