Behind the right side of the intake manifold on top of the
block.  It can be difficult to get at.  You also need to
reach in there with and pull out the filter to clean/replace
it since it usually sludges up over time plugging the
system.  If it plugs, the PCV cannot work right and may
cause seal and gasket leakage.  I am assumming to have one
of the V8 engines.  The 300 six is obvious in the rocker
cover.