The round track small block V8's we built with extremely loose piston skirt and bearing clearances to prevent the engines from tightening up during extended periods of full throttle operation had massive amounts of blowby, more than any normal type of crankcase ventilation setup could handle. That's just a normal byproduct of race engine building- - - - -"Go fast for a little while- - - -win a few races- - - -blow up into a bunch of pieces of expensive junk!" Repeat as necessary. Run out of money!
The breathers we fabricated were made of two pieces of exhaust pipe about a foot tall, welded to the driver's side valve cover, with vented oil fill caps attached to the top. Quite often, we would zip-tie a couple of folded up shop towels around the breathers for extra filtering. I found that cutting angled slots into the pipes and welding pieces of thin sheet metal into them made the vapors and oil splash negotiate a kind of maze before reaching the top, and kept more of the oil from finding its way all the way to the breathers on top of the pipes. Something similar could be done to a standpipe fabricated to fit the breather hole in a stovebolt block, with the PCV valve at the top of the pipe. A sealed oil filler cap could be added if desired.
Jerry
