I don't know if that is a push-in or twist in (bayonet) breather, but back in the day, with the bayonet style, I used to use 60's--70's Ford style breathers which have a PVC gromment in the top. You could get chrome ones used on such things a 390 Mooostangs
This one from Summit is a little pricy, and seems to be set up for the air filter end
Scott Drake Valve Cover Oil Caps C8AZ-6766-B
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