Replaces OEM #509GC413A. IMPORTANT: Please call toll-free 1-800-282-9319 to order. Please have the following information available when ordering: Truck Model, Last 6 Digits of Truck Serial Number, and Engine Assembly Number. The Engine Assembly Number will be located on the engine tag on the front valve cover of the engine and will start with 11GBA. Bore 5.375 in.