Xtreme CFM Cylinder Heads provides the highest quality in portwork and our attention to detail is second to none. We continue that attention to the Melling Oil Pump for the LS1/LS6/LS2/LS3 platform, Xtreme CFM oil pumps are engineered to provide optimum performance and reliability. Each pump has undergone several modifications, we dissemble, hand port both inlet and outlet for optimum performance along with shimming the by-pass spring for a 10% increase in pressure over stock. These modifications provide additional oil volume and pressure with minimum parasitic horsepower loss, cavitation and oil shear, in turn increasing engine-component longevity. Additional o-rings are also provided with pump.