Let me rephrase; Originally, Mopar V8s factory equipped with a PCV have one breather placed on the opposite valve cover. Every FSM description I have ever read of the Chrysler crankcase ventilation system specifically mentions this cross-flow design on the V8s. Not really a cross-flow on the in-line 6 is there? As for Ford, I seem to recall that breather(as you describe it) with the PCV in it severed as the filler cap, and a replaceable air cleaner mounted filter element plumed to the rear of the opposite valve cover was in fact the crankcase breather.