I'm also looking at a design that will allow the rocker shafts to rotate inside the standoffs on the cylinder head, resulting in evenly distributing the wear all the way around the shaft. That design uses short sections of thick wall high pressure seamless tubing, needle bearings in the rocker arms, and bushings fitted to the shaft standoffs so the pivot shafts can rotate at random. Short sections of pivot shaft can be surface hardened pretty easily with Kasenit powder and an acetylene torch if necessary.
Jerry
