Have had the same problem with my 1960 235 in a 52 3100. After some frustrating time under the truck at the side of the road. And replacing the fuel pump I finally found the culprit. The needle in the carb that the float controls would stick. Some times closed..no fuel in the bowel and some times open...fuel leaking on to a hot manifold. Not the best of conditions. I took some 600 grit paper and polished the needle on the three sides that rub on the side of the seat. That solved my problem. Don't touch the tip. Don't touch the tip. That will make it leak all the time. Old tank, old gas, new alcohol fuels and a new kind of sticky varnish will add to our issues. Good luck with yours.

Steve H