Wagler Competition Products is the developer of the first Aftermarket Duramax Cylinder Head. This head has a unique port design that allows for better airflow and greater horsepower. These Heads are assembled with: Stainless steel intake valves, Inconel exhaust valves, Bronze valve guides, Heat treated ductile seats, and Competition valve springs with titanium retainers. The casting was also designed to incorporate Injector Cups for the LB7. The valve centerline is relocated to allow for larger valve sizes. Casted from virgin A356 aluminum alloy and designed to bolt directly on to the factory Duramax engine block. The Wagler Competition heads have shown Horsepower and performance gains. The heads are offered in bare casting, street series (S-series) or competition series (X-series) assemblies.