That rocker arm bushing setup wouldn't be difficult to duplicate with a tool post grinder and a couple of chucking reamers, as long as a bolter has a lathe and a little bit of machining experience. Grind the rocker shaft down a few thousandths to smooth up any wear, ream the rockers slightly oversize, and press the bushings in. Tooling up to make the first set would be a little pricey, but the cost could be amortized by selling the re-bushed assemblies on an exchange basis, similar to what starter and generator rebuilders do.
Jerry
