Rocker Shafts

Has anyone had a problem getting rocker shafts to oil ductile adjustable cast iron rocker arms on an aluminum head and what's the solution? If I bolt the shaft to the head it seals. With the ductile adjustable rockers on the shaft the oil pushes out of the bolt not thru shaft. It's like the ductile rockers are creating back pressure.
Author: plyduster360