Our parts are mostly all original Harley Davidson Obsolete Parts from Dealer Inventory and are listed by the Harley Numbering System. Use Original Harley Parts Catalogs if you need to look up part numbers. Parts catalogs are available for sale at www.cyclemanuals.com . A typical number would be 13765-67, the -67 reflects the year that part was introduced. Our Index focuses on the main five digits. The dash extension number will be on the item page.