If anything, a good read that I just found.
’The crank case ventilation Bible”
https://www.shophemi.com/images/medi..._ccv_bible.pdf

I just have breathers on my valve covers, no CCV system. I don't have any oil or film buildup on my valve covers and the amount of blow by I have witnessed while running albeit at very moderate speeds is very minimal. My oil comes out almost as clean as I put it in. I actually use my old oil as bar lube on my chain saws. I have thought about adding extractors to my headers to give me a negative crankcase pressure.

It has happened before when people have said "yes" to logon with Facebook question.