Clean the rocker shafts, I had thought about that, but did not do it on my stock 318 build, wondering if their are new plugs in the freeze plug set. Do not remember seeing them, will look. Haven't started it yet, wish that I had a dent puller to pull the end plugs, but I know where one is. Other ways to do it too.
The Hughes replacements have pipe taper end plugs to be installed after cleaning. Have read previous post in which someone had horrific time finding stock rocker shaft plugs. Precaution may be necessary before pulling plugs.