Reply to "Oil Flooded Valve Cover"

With the engine fully installed but the rocker covers off, the simplest way to clear an oil drain-back problem is to use a 5/16" dia hardware store compression spring about 8" long for a screen door. You thread and rotate it by hand into each oil drainback passages like a Roto-rooter. In each stock head, there's only two drain-backs; one is straight through and seldom is totally blocked, but the other has two bends to work around internal water passages. The drillings that make this one up often don't match up, and stuff accumulates that eventually causes complete blockages. I've seen "reconditioned" cylinder heads in which this drain was absolutely full of brick-hard varnish. Hours in a hot tank degreaser will not clear such slop, but a door-spring is flexible enough to work around the curves.
If you do clear blockages like this on an assembled engine, all the slop then falls into the oil pan, so do this just before a normal oil change. If little pieces of slop eventually work their way through the coarse screen on the oil pump pickup, the varnish is hard enough to momentarily seize an oil pump and shear the distributor drive-gear roll pin.