A positive crankcase ventilation system for an internal combustion engine comprises an intake manifold having a plurality of intake runners configured to deliver combustion air to the internal combustion engine. An intake manifold positive crankcase ventilation passage is disposed in the intake manifold and is in fluid communication with a source of blow-by gas from the engine. A positive crankcase ventilation distribution channel is formed adjacent to the sealing face of the intake manifold and a modular positive crankcase ventilation distribution conduit assembly is disposed in the positive crankcase ventilation distribution channel and extends from the positive crankcase ventilation passage to the plurality of intake runners for delivery of the blow-by gas thereto.