i did the FV308 PCV mod from the intake to the passenger side valve cover. Went as planned. Assume it works as intended. I've been eyeballing this hose since I had to remove it to take the upper IM off for the coil job. It also runs from a nipple near where the hose from the air filter assy slips onto the upper manifold and runs to a fitting of some sort in the drivers side valve cover. Stock? If not, what should be there?

 

 

It's a breather tube, and should be there.

 

So, no pvc valve required on that one? Or should / can I double up with the FV308 there as well?

 

Do NOT put a PCV valve there unless you really want to blow out a rear seal.

 

PCV valve is on the manifold side of the throttle body, it controls the flow of crankcase gases in to the engine while the engine is a closed throttle high vacuum conditions. In open throttle low vacuum conditions that breather tube routes the crankcase gases in to the engine without the PCV restriction. The wikipedia page on PCV is actually a pretty good explanation of the design and history of PCV systems. The breather tube should not be modified.

 

I found this

Shows how flow should be