[scooder]

A properly installed PCV on an 8BA would draw air through the oil fill cap, this has a wire mesh filter in it. So I think it will be fine.
Infact any properly installed PCV on a Flathead will/should draw in via its mesh filtered oil fill.
The odd ones out are the labyrinth still engines, these could pull UN filtered air through from the clutch housing, though the design of the labyrinth, the kinda disc spinning in a couple of deep groves would probably prevent a good amount of particulates getting to the crank case. But maybe the caught bits in the labyrinth would slowly fill up the grooves?
Martin.