[Old Crow]

All PCV valves are hooked to manifold vacuum, it's just that the port is usually in the base of the carb.
Upon further reflection, I'll have to seal the 4 little louver vents in the top of the valve cover and run a vented filler cap.
Vented filler caps have filter medium in them to filter the air as it enters the engine.

Of course I've just finished painting the valve cover, so that'll be a do-over.

I'll probably find a PCV valve for a six cylinder engine instead of the one I stole out of a small block for the picture.