[duke36]

Vendors back in the '70's were selling a hose to run from the intake vac.. fitting to the side of a valve cover bolt . That supposedly discharged oil into the intake manifold ! I can't find the info. but someone fitted a pipe that ran from the intake manifold fitting around the block to the oil filler cap with a PCV valve mounted on top of it.
The vendors now sell an enlarged oil fill pipe similar to the '32 B engine pipe which breathes better.
Chrysler flat six engines have a separate breather pipe in addition to the oil fill pipe, recognizing the need for better pos crankcase venting.