Hummer H2: Cylinder heads

These new fully CNC-ported LS1 performance cylinder heads feature 215cc intake runners, 80cc exhaust runners, 64cc combustion chambers, 2.04" intake valves, 1.575" exhaust valves, bronze valve guides, and ductile iron intake and exhaust valve seat inserts.

HPE Stage 3  5.3 Cylinder Heads

HPE custom designed cylinder heads increase compression as well as increasing flow. Our stage 3 CNC 5.3L heads are for optimum power and torque. We have seen as much as 40-50rwhp over stock with these heads.