After reading this, searching here, and searching at corral.net, I'm going with a breather and PCV on my 351, which is carbed. For now I'll leave my 305 with the stock setup.

I just installed a ProCharger D1-SC setup on my Formula about a month ago. The directions tell you to unplug the PCV vacuum hose from the engine and just aim it towards the ground. For the passenger side breather do the same. Then the supercharger kit comes with two rubber plugs to cap off the vacuum fittings on the throttle body and intake. Why do they have you do this if we really need the PCV system? I can tell you that the transmission linkage and brake lines are very well lubricated now.

Thats because you're running boost, so there's no vucuum to clean out the crankcase gasses.... You don't want to push boost into the crankcase...

I thought that the PCV was a check valve that won't allow air flow into the valve cover, it would only allow vacuum. Couldn't I run a filter style breather on the passenger side rather than the breather getting air from the throttle body. And then still use a PCV on the driver's side?

The PCV system was installed by GM and other Car MFGs, was for one thing "EMISSIONS". PCV=Positive Crankcase Ventilation. So
if you don't care about this just remove it. We are beating this topic to death for no useful purpose now, let it DIE.:lala: :lala:

Just wanted to say, I decided what the hell and stuck a breather in it in place of the oil cap and didnt notice any difference in the way the car runs - but it does look 10X cooler now

Not flaming, but it would be a lot easier to finish this topic off if the information provided in it was correct. Like I was saying above, the only real concern about emissions with the PCV system is not letting the crankcase gasses get into the atmosphere. That is why the system is sealed from the atmosphere and the gasses are burned through the engine. But lets not forget that the PCV system does do a very good job of 'cleaning' the air out in the crankcase and keeping the oil 'cleaner' . So it isn't all about emissions. The PCV system is useful beyond protecting the trees.

And in reference to the above question about the valve itself, it is a check valve and (when clean and operating correctly) only allows flow from the crankcase to the intake manifold. The purpose is to cycle fresh air into the crankcase and prevent pressure from building in the crankcase.