PCV valves

Yes but the Cleveland doesn't like that. It will leak oil if you do. Mine leaked from the o ring on the distributor. They like positive ventilation. Open breathers don't equalize the pressure enough.

Okey - I'll stick to the PCV valve in one cover and a breather in the other. But I'll need new covers then. I don't have enough Space for my rockers with the ones I have now.

Thanks for the info.

Try these. They are made by Blue Thunder.

I like em because of the four access holes.

http://pantera.infopop.cc/eve/...562/m/8831024056/p/2

The cast-aluminum rocker covers once used on Boss 302s, and the repros from all the vendors will clear roller rockers AND most stud girdles if you remove the tin baffles inside. My baffles have all been gone 20 years and 70,000 miles with no problems.
Yes- run a PCV or internal crankcase pressures will force oil past both main bearing seals and a number of gaskets, making a mess.

I had luck taking off the baffles, clamping them tight, tack welding them in that position, reinstalling. Clears my roller rockers, Detomaso scrip valve covers, studs, poly locks, no gasket, just silicone,