I have always thought that if the crankcase was vented, since the space under the valve covers is connected to the crankcase through the pushrod tubes, the valve covers didn't need to be vented.
I have some new valve covers that are already drilled and tapped for vents. So, I am reconsidering.
I have read that some people vent both sides and some vent only the 1-2 side saying you shouldn't vent the 3-4 side.
Some say that venting the valve covers facilitates the oil draining back through the pushrod tubes.
What do you all think? Should I plug the holes, vent one side or vent both sides?
I have a CB breather/oil fill setup venting the crankcase and have opened up the outlets. I also have a breather box above the transmission that two transmission vents are connected to. If the consensus is that I should vent them, how should I route the hoses? Should I tee them together into a single hose I connect somewhere? Some suggest using an air filter type thing right at the valve cover. Others say that something like that would get clogged up.
Again, what do you all think?