If you have a significant amount of blow-by of combustion gases getting past the rings into the crankcase, you will need to be careful how you design your homemade PCV system. If you do it wrong you will have too much foul crankcase fumes re-introduced into the combustion chamber at the wrong time, causing poor performance.
I would recommend researching and looking at how GM designed the PCV system for the 230/250/292 engines and copy that as close as practical.
Carl
