The vacuum produced at the PCV is far more powerful that the air pressure on the "clean" side of the air filter. There's no vacuum way up there, at least unless the filter element is so clogged that it causes the carburetor to flood. Modifying the road draft tube like the one in the picture without puttong the PCV up close to the height of the valve cover like the factory setup does might make the engine an oil-burner, however. There's usually a good reason the factory does something, not just spending money on a different dsesign for no reason.
Jerry
