Abstract: A support platform for mounting a rocker arm shaft in an internal combustion engine comprises an elongated base element which fits on the top surface of the cylinder head of the engine, support pads which are mounted to the base element intermediate its ends at spaced intervals, and end blocks which are attached to each longitudinal end of the base element. The rocker arm shaft is mounted in transverse bores which extend through the support pads and end blocks, and is attached to the support pads by bolts which pass through vertical bores in the support pads, the rocker arm shaft, and the base element into registry with threaded holes in the cylinder head. The end blocks engage the rocker arm shaft at each of its extremities, outwardly of the outward most rocker arm, for preventing deflection of the end portions of the rocker arm shaft upon loading of the rocker arms.