[dmjlambert]

I don't get what you are saying. How does your valve cover breather hole accept air? From open air immediately surrounding the valve cover, or does it suck air through a hose from the carburetor air cleaner housing? If it sucks air through a hose from the carburetor air cleaner housing and goes down into the breather hole with just a plain open pipe, then you may want that spark arrester. I think the spark arrester also doubles as a way to connect the grommet to a hose.