Question about buying Carter BBD for my 318 (unless I should look at something else)

67CBodyGuy said

I sanded the airhorn casting mating surface and I don't think it is seeping any gas now. The clip that holds the float hinge rod may have been interfering with the air horn seating fully against the body so I adjusted that also. The brass floats seem fine, no holes.

I think over time the tabs with the holes for the airhorn screws can bend under the force of the screws and cause the casting to not be flat.

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The fuel level is generally well below that top gasket, and shouldn't get fuel near it unless seriously rocked/sloshed around in the bowl.
You observed that "round" thing on one of the carbs, That's a vent to open to air, not to seal gas in.
If it was a foam float, they get soggy and brass floats can leak a little fuel after time, both cause a high float level, and rich running.
You need to weigh or shake floats, jmo