Round three at JMS involved swapping out the factory crate engine cylinder heads in favor of the more efficient flowing Dart Pro 1 heads with the Weiand intake (rectangular port). Everything else, including the COMP valvetrain remained the same. We’ve even left the same Holley 950-cfm carburetor. Although our gains were minimal, it was clear that the current camshaft was too small to take advantage of the heavier-breathing Dart Pro 1. On JMS’ dyno, we peaked at 558 hp at 4,800 rpm with 641 lb-ft at 3,900 rpm.