still denny a closed system is not a system with the pcv vale in one valve cover and no openings anywhere else. on the closed system the other hose goes into the breather and circulate the air into the carb. breather. some of it get used over again and some goes out of the tail pipe, but its got to have a out let. i think some people belive a closed system would be just a pcv valve stuck in ome valve cover with no other opening. or am i reading it wromg?