A friend just brough over a Holley NH Carb for me to repair. The brass tag is missing, so it might be a look alike brand X.
The problem is a 1/8 inch hole has been drilled under the tag area and would have been hidden by the tag.
The questions are:
Why would that hole be there?
Does it serve a useful purpose?
Was it there originally?
Should it be left as is or plugged?
To allow normal air pressure inside the bowl otherwise it would air lock and no gas could be removed from the bowl.
Ron the Coilman
You can get perfect replicas of these little patent plates along with the tiny rivets Jim Patrick
I just cleared out that passage on an NH, and purchased those tiny rivets. They are tiny, and I found that the diameter of the shank of the little rivet was smaller than the original one removed. I was able to re-use one original, and I had to add a little epoxy to the new undersized rivet to keep in in there.