[markeb01]

In the original configuration, the road draft hole in the back of the block behind the manifold would have had a hard pipe installed that hung down on the passenger side of the bellhousing. As the vehicle moved down the draft a draft on the bottom of the tube would suck the fumes out of the crankcase. It wasn't a very efficient system.

Your current setup appears to be installed backwards. A PCV (Positive Crankcase Ventilation) valve will not function correctly hooked up to the air cleaner. It must be connected to full manifold vacuum.

If you have the hose adapter in the road draft tube opening now, it should be routed to a PCV valve and connected either directly into the intake manifold (usually behind the carburetor) or directly to the base of the carb at a full manifold port. This is the only way the crankcase will be properly ventilated.

The valve cover can have either an open breather, or a breather with a tube on the side connecting to the air cleaner. You can actually have breathers on both valve covers if desired. The purpose of the breather(s) is to allow fresh air into the engine, while the PCV pulls the fumes out. A breather connected to the base of the carb without a PCV installed will function as a massive vacuum leak and the engine will idle crappy.