Ya, I've removed the little sight plugs on the side of the fuel bowl and the fuel is a little below the hole.
Ya, I've removed the little sight plugs on the side of the fuel bowl and the fuel is a little below the hole.Are you sure that the float level being too high is not causing your leak?
The list # is 500931. Turns out it is a 4180 carb.Posting a pic would be really helpful to you here.
The front of a 4160 will have a metering block and the back bowl will have a metering plate.
I'm thinking that you probably need a new metering block now that it's been drilled and tapped. I don't believe that modification is going to work.
What it the list # of the carb on the front of the air horn?