[ImperialCrown]

Actually the airflow should be from the breather tube into the crankcase then sucked through the PCV valve and burned in the engine.
Excessive blow-by maybe from a wrong or failing PCV valve, wrong or thin engine oil or failing poorly sealing piston rings.

 

[ImperialCrown]

There is a high pressure oil galley passing through the head gasket to lube the cam in that corner. Leaks were very common.