Did you clean the crud out of the inside of the rocker shaft?
While the engine is running, is there oil running out along the bottom of the rocker arms on the non-flowing rocker arms? You may have excess wear on the shaft or the rocker arms, allowing the oil to escape out the bottom rather than through the little holes on the top.
I don't suspect that you have the rocker shaft on upside down. That would give you a large gusher of oil out of the little rocker arm holes on the top.
Carl
