The crankcase ventilation system is simply some plumbing which burns off the crankcase fumes. The main plumbing component is located under the 3rd intake runner, has a hose coming up from crankcase and a hose going to the air intake bellows and a small vacume hose. Inside it is a small plastic disk or on some models a brass coiled up screen, that is the flame trap device and it can get clogged so some Bricksters simply remove it, no change in power or performance. In theory it stops a flame front in the event of a backfire from travelling down into the crankcase, but that just never happens. The system should be serviced, if clogged you can build up crankcase pressure and force oil out the seals. The vacume line is subject clogging as well as the brass fitting where it connects to the valve body.
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David Hunter