2 Star uses Procomp Electronics 3002S heads for this recipe. These have all the features of the more expensive heads out there, like bronze guides, hardened seats, three-angle valve job, and a heart-shaped combustion chamber. The combustion chamber design improves the flame front travel, and in turn improves efficiency. The heads come to Jeff unassembled, but with all the parts needed for assembly like guides, screw-in studs, and valvesprings. Jeff takes the time to measure installed height and seat pressure on the springs so they match the cam specs.