 The purpose of having multiple camshafts is to ensure a quieter engine, the more cam lobes an engine has the easier it is to control the valves which means they can be opened and closed at variable times allowing exhaust to escape where it is needed

Push rods are cylindrical pieces of steel that vary from seven to ten inches in length but in older engines push rod length was adjustable so that valve lash could be adjust as well.Push rods come with a manufactured hole that extrudes through the rod, this hole is designed to force oil to flow directly between the camshaft and the valves .These rods are usually made of high carbon steels.A push rods purpose is to transfer rotational energy from the camshaft and turn it into linear energy which operates the valves.