Some users find that once they remove the plastic retainer from the original equipment cam on GM trucks, they can't get adjustment to hold. These lock plates are designed to provide a mechanical lock for the cam bolt to the guide pin. Simply dial in your change with the original equipment cam or SPC's replacement kit #86376 and then replace the nut side cam with the lock plate. Use part number 86326 HD GM alignment pins to replace the often abused OE pins. This kit is designed for GM 2500/3500/4500 HD trucks (Upper Arm Adjustment) and the 2015 & up Chevy Colorado (Lower Arm Adjustment).