Interchangeable rocker arm assembly

A rocker arm assembly for an internal combustion engine includes a central mounting shaft and a rocker arm rotatably mounted to the central shaft wherein the rocker arm has a generally planar main body with a valve contacting end and a push rod contacting end. A convex surface is formed on a lower edge of a valve contacting surface and the push rod contacting end includes a generally semi-spherical recess that creates generally semi-spherical outer projections on the sides of the rocker arm main body. The central mounting shaft according to one embodiment of the present invention is a generally hollow, tubular shaft having spaced apart lubrication apertures for providing lubricant to each rocker arm. A second embodiment of the present invention has a central mounting shaft that includes a plurality of relatively short, hardened shafts connected together at respective adjoining ends by a spacer sleeve to provide a rocker arm assembly having greater stiffness.