I am sticking with the plastic PCV valve for now as it provides more forward air flow and the check valve to stop back flow has a better seal. It is interesting that the hose from the air cleaner to the oil cap is larger than the hose from PCV valve to carb with the PCV valve reducing flow further.
Not really on the hose sizes, The factory setup was as such. Positive flow and evacuation of the crankcase is all that matters! Cam lift and more can effect this much, and sometimes a Vacuum pump is required.
Most do not and finding a good balance that gives a smooth idle is the ticket! JMO!
