Is your PCV in your valve cover? Is the valve cover baffled?
You may be sucking more oil through the PCV than they’re intended for, which is fouling the PCV. It’s also worth noting that not all PCV’s pull the same amount of vacuum, some pull more than others and pulling too much can pull oil too.
I run a HV oil pump on my 340, and it throws a lot of oil around even at the rockers. I baffled my Cal Custom valve covers, then used a 1/2” spacer to raise the valve covers further from the rockers, then finally relocated the PCV from the valve cover to the top of a catch can (there’s a pick up in the valve cover that runs to the bottom of the catch can). I also tried several different PCV’s to tailor the amount of vacuum being pulled through the system. There is a PCV valve that can be tuned, although it’s pretty pricey for a PCV.
Bottom line is it may take some trial and error to get the PCV system set up so it works for your engine.