Complete kit with two die-cast chrome lower covers, two die-cast chrome upper covers and two stronger than stock rocker arm supports. These covers are a must when installing S&S electric compression releases. Installation on stock and most comparably sized engines can be performed without removing the engine from the frame. Rocker covers are clearanced to permit valve lifts up to .640" using aftermarket valve springs packages and stock Harley-Davidson or S&S roller rocker arms. If using valve/spring packages with taller than stock installed height, some minor clearance may be required. S&S rocker covers accept valve springs up to 1.660" O.D. without modification. Cylinder heads must be set up correctly for high-lift cams, and it remains the builder's responsibility to confirm all clearances.