Borrow a gauge and put the hose on the dip stick tube
and run the car with the same set up you normally
run an see what the gauge says..... if you have pressure
it isnt evacuating even with the PCV and breathers
which would indicate a ring issue.... if you dont have
pressure its more likely to be a intake issue... a
leak check or compression check can not tell you
anything OUTSIDE of the cylinders(cant tell you if
the intake is sealed or not)
Also for a quick check.... change the PCV and make
sure its a V-8 one... there is one for a 4 banger also