Exhaust scavenging only works at high RPM . My favorite way to vent the crankcase is with a 1.5" metal tube, connecting the valve covers, with two standups on it with clamp on breathers on those. The tube is connected to the valve covers via 2" long pieces of rubber hose for connecting the tubes welded to the covers.That sounds confusing, each valvecover has a 2" long metal tube welded to it, these attach to the "bridge" with short sections of rubber hose, the bridge has two stand ups with the breaters on them. It will allow tons of air to escape, and
oil can't make it to the breaters and get all over everything. Also, no
oil getting sucked into the intake because your shiny aluminum valvecover have crappy baffles.to stop the
oil from going into your pcv hose. For the drag cars, I like mechanical vacuum pump sucking on the crankcase.