I had two PCV, one on each side along with two breather caps on my old pump gas Duster motor to help reduce the oil blowing out of the caps on the street.
I did not drive it easy or hard all the time
It had a set of Cal Custom cast aluminum valve covers from day one on it with a six pack, 4.375 bore with 1/16,1/16, low tension 3/16 oil ring at first, 4.250 stroke with 9.25 to 1 compression ratio. Adding the other PCV and extra cap help a lot, let it breathe
I ended up changing heads to a set of MCH CNC ported Eddy RPM heads and crankshaft to a 4.300 stroke to increase the compression ratio to 10.29 to 1 and rering it to standard tension oil rings, which help a little but adding the two breathers and caps was the best change for the oil blow by