STRAIGHT from the wiki page
"The PCV valve is only one part of the PCV system, which is essentially a variable and calibrated air leak, whereby the engine returns its crankcase combustion gases. Instead of the gases being vented to the atmosphere, gases are fed back into the intake manifold, to re-enter the combustion chamber as part of a fresh charge of air and fuel. The PCV system is not a classical "vacuum leak". All the air collected by the air cleaner (and metered by the mass flow sensor, on a fuel injected engine) goes through the intake manifold. The PCV system just diverts a small percentage of this air via the breather to the crankcase before allowing it to be drawn back in to the intake tract again. It is an "open system" in that fresh exterior air is continuously used to flush contaminants from the crankcase and into the combustion chamber."
What part of the intake not being connected to the valve covers except by the PCV hose do you guys not understand? AS PREVIOUSLY EXPLAINED: Gasses form from the HEAT, the gasses do NOT come from the cylinders where combustion is taking place, nor does it come from the intake. If you block off where the PCV barb is on the intake then there will NOT be a vacuum leak.
Go outside now, take off the PCV from the crank case and plug the hose, start the car and voila! Bet itll run just fine.
There are no power benefits in doing this. The only real benefit is looks and that you dont have your intake runners lined with a thin layer of a tar like substance.