Knucklehead cylinder head set features original cast iron with black finish. Head set includes valves, springs, collars, and guides with parkerized upper and lower valve cover sets installed. Head set includes rocker assembly.
Head set features early rocker box shape of the 1936-1939 EL models. rear exhaust rocker arm shaft is fitted with the seal tube spacer arrangement, an upgrade of the era to allow the use of the later model valve spring covers. Intake ports are the large 74" version of 1941-1947 FL models.