Abstract: Novel rocker arm shafts and rocker arm assemblies employing such shafts are disclosed for aligning a plurality of rocker arms and shafts that are individually removable from and attachable to a base such as an engine block. Rocker arms mounted on the shaft can be taken out of the rocker arm assembly without having to remove the entire shaft and the other rocker arms in the assembly. The rocker arm shafts are of a length to mount one rocker arm and the ends of the rocker arm are attachable to one another so that when assembled the shafts can be locked rigidly together and each bolted to an engine block.