Feuling highly recommends using one-piece pushrods instead of adjustable pushrods to maintain maximum cam/ valve lift and reduce valvetrain harmonics and associated hydraulic lifter issues. Fixed length, 4130 chromoly one-piece pushrods with swedged formed ends. Heavy-duty 7/16in. diameter tube with a wall thickness of 0.165in. Heat-treated with a black oxide finish. Stock replacement lengths. Designed to work with factory base circle camshaft dimensions. Will work with all stock, Screamin Eagle and Feuling camshafts. Made in the u. s. a. NOTE: Due to the unstable nature of this 4-valve engine design with one rocker arm activating two valve springs Feuling highly recommends running one-piece pushrods instead of quick-install adjustable pushrods to maintain maximum cam/ valve lift and reduce valve train harmonics and associated hydraulic lifter issues. NOTE: Requires removal of rocker covers and rocker arms for installation.