Ideally you're going to want 2 catch-cans for a proper install and to maintain vacuum inside your crankcase.
VC breather ---> MAP crankcase vent (optional but recomended) ---> catch can ---> intake pipe
AND
stock PCV ---> catch can ---> MAP crankcase vent ---> intake manifold
http://www.maperformance.com/map-cra...acuum-kit.html