These high quality rocker arms and shafts are the same as we use in the knucklehead series engines, and fit stock knuckle engines too. Stock 1:1 rocker ratio. Rocker arms are sold individually and as sets of four rocker arms and shafts. Rocker arms include rocker shafts, since rocker arms are not compatible with stock rocker shafts. All four rocker arms and shafts are unique. Rocker shafts are available as a set of four only. Fits:1936-'47 over head valve HD® big twins, compatible with S&S® or Stock tins, not compatible with stock rocker shafts. Features and Benefits High quality CNC machined 1:1 stock knuckle rocker arm ratio. Improved oil control. Kit contains Four rocker arms, four rocker shafts, and washers and spacers.