Drive line parts Knucklehead Panhead shovelhead include Clutch, Oil & Chemical, Primary Belt Drive, Primary Chain, Primary Cover, Rear Wheel Belt Drive, Seals & Gaskets, Sprocket, Tools. Knucklehead EL FL 1936-1947 | Panhead EL FL FLH 1948-1965 | Shovelhead FL FLH 1966-1984.