2001-2016 GM 6.6L Duramax Valve Springs, Retainers, and Keepers Complete KitThe valve spring, spring seat retainer keeper kit comes installed with each PPE Duramax Cast Iron Cylinder head. The tapered valve springs' higher spring rate and lighter valve train weight enable faster response during higher RPMs and eliminate valve float. Premium chromoly material construction ensures the longevity and durability of valve seats, retainers, and keepers. Kit Includes: 32 springs 32 spring retainers 32 spring seats 32 sets of keepers