The XDP Roller Rocker Arm Assembly Set XD326 is the ultimate upgrade for the rocker arms in your 1998.5-2018 Dodge 5.9L/6.7L Cummins. Your valvetrain components are on borrowed time if your engine is heavily modified. The XD326 addresses multiple weak points to give you a valvetrain that will support extreme horsepower while giving you the durability and reliability that you've come to expect from your Cummins diesel engine. This set is built using the same materials, components, and manufacturing processes that have been tested and proven in top fuel and blown alcohol racing engines. The XD326 lets you take the performance and reliability of your truck to the next level. This system is a direct bolt-on and can be used on any application including stock engines and competition/race builds. Roller Rocker Arm Assemblies The XDP Roller Rocker Arms feature a revised design with added mass that triples strength over the factory rocker arms. Manufactured from a proprietary grade of heat-treated tool steel for extreme durability. The roller tips drastically reduce friction between the valve bridge and rocker arm, while reducing side thrust on the valve guides to decrease wear. The high load bronze bushing provides a replaceable wear surface and friction reduction when compared to the OEM rocker arms. Billet Tool Steel Adjusting Screws The XDP Roller Rocker Arms come with ultra-durable high-quality adjusting screws manufactured from H-13 tool steel that has been heat-treated, triple-tempered, and nitride coated to for long-lasting performance and reliability. Rocker Arm Trunnion Set Your OEM Rocker Arm Trunnions are only made to handle stock power levels. Added stress from aftermarket upgrades and increased power quickly maxes out the capabilities and oil flow of the stock trunnions. The XDP Rocker Arm Trunnion set is made from premium tool steel that is hardened and nitride coated. The upgraded trunnions have been machined to increase oil supply for maximum lubrication in the most extreme applications. Billet Rocker Arm Bridges The XD326 Roller Rocker Arm Assembly Set is made for serious power and dependability, your factory rocker arm bridges are not. Featuring a CNC machined 4140 billet chromoly construction, the billet rocker arm bridges are able to withstand the added stress from your modified Cummins engine. Includes: XDP Roller Rocker Arms & Adjustment Screws, XDP Billet Bridges, and XDP Rocker Arm Trunnions FEATURES: Bolt-On Installation Stock Rocker Arm Ratio Increased Strength & Reliability No Additional Modifications Required WARRANTY INFO: Products manufactured by XDP carry a 1-Year warranty against defects in materials and craftsmanship. The Warranty is Limited to one (1) year from the date of sale and limited solely to the parts contained within the product's kit. Click Here for full warranty policy.