i think i get you question, jokes asides though, that alows your cylinder head to "breath" ie: vent out gases that build up inside, but since there is oil in there as well, a catch can is put in place so that the oil ...well... gets caught inside (didnt know how else to put it)
absolutley correct. once you go this route you no longer are running a valve, but just a simple breather systemBoth those cars don't have the pcv system which is for emissions. Once you tap the valve cover on the supra and replace with fittings to run to a catch can, you no longer have the pcv valve that is needed for this "emission" system to work.
I don't believe its called a pcv on the skyline motor either because they don't run a pcv type emissions control.