[Raymond]

PCV valves are readily and cheaply available on line. They come in many different forms but I think they all work in a similar way. I don't know which one would work best in your engine but I would suggest keeping it as simple as possible. You could perhaps fabricate a grommet fitting in the valve cover or perhaps adapt the filler cap. You would also need a hose taken to a suitable point on the inlet manifold from which to obtain a vacuum. No doubt there would need be a bit of experimentation.

An alternative solution would be an exhaust extractor system with catch can. I have used this method on my supercharged MG TC XPAG engine to replace the draft tube. It is a popular option with forced induction systems where PCV valves do not work as well as in normally aspirated engines.