A pcv on one side, and a baffled breather on the other side should be all you need. That is why I don't run aftermarket valve covers. Other than that you are getting too much blowby past the rings.
Back in 1980, when my 340 had well over 100K miles on it, I started getting a lot of oily blowby. Still ran good, but it made it hard to keep the motor clean. Took the motor apart and I had five broken rings.