I had Two! well I started with one PCV on the drivers side and a push in breather on the other. Then I DROVE my K5 from Cali to Moab, wheeling for 3 days, then drive back. Dirve back was "different". Every now and again my rig would SMOKE OUT the entire hwy, then the smoke would stop. Well looking at the engine Oil was everywere and the smoke was from the oil landing on the headers. I assumed I blew a front main seal, adding a quart or two, every 60 miles was my paln to get home. Man the whole under side of my rig got coated in oil.
ANYWAY... we just crossed over into Cali, Barstow, HOT desert, My buddies engine broke a rocker arm stud so we were stuck.
My other buddy suggested I add a seconf PCV to the other side as my problem may not be a bad seal but "blow-by" excessive pressure building up inside. Got a T & more hose and another PCV and installed...no more oil spitting out all over my engine

So yes use one or two hahaha

