2001-2016 Duramax Rocker Arm Spacer KitThe Duramax Rocker Spacer Kit was designed to eliminate the factory springs in between the rockers to keep the rockers properly aligned to OE spec under high load and high rpm conditions. The factory springs allow the rocker arm shafts to move around which can cause improper valve lift and irregular wear on the valves and rocker arms. Our high performance rocker arm spacers prevent this from happening and allow your engine to operate more efficiently