Stock bore replacement for 2006-17 Dyna models Stock looking, but stronger Thicker wall sections and superior 356-T6 aircraft grade aluminum Tough powder coat finish Reinforced front motor mount for extra strength Timken sprocket shaft bearing which is strong enough for the most demanding applications Clearanced for strokes up to 4-13/16" and cams up to .720" life Includes pinion and Timken bearing Manufacturer's Statement of Origin (MSO) included Includes studs and cam bearings installed Requires oil supply line installation kit 912-427