Great response, I will run the 1 check valve after catch can. I do have breathers on both valve covers. I hear that should help? I’ll update soon as I’m done today or tomorrow? Thanks, GeneYou only need one check valve. The PCV line should go from the PCV to catch can to check valve to intake vacuum source. The turbo inlet will not have enough vacuum at low rpm. You can have a line from the valve cover to the turbo inlet similar to the stock set up to help with crank case evacuation under boost. A oil separator could be in that line too. There are many theories on this. On the Corvette Forum, there is a member Kingtal0n that has a many posts on how the PCV system works and what the vacuum a needs are for the PCV and before turbo inlet for engine evac under pressure.
Another theory on oil in the PCV line I've heard is oil from the turbo return line getting on top of the intake bathtub gasket and running to the back of the engine is getting sucked up in the PCV valve. Don't know if that one is possible or not.