[FlatheadTed]

Unfortunately this phenomenon seems be what 90 percent of old ford have .I did some tests on a 36 fuel pump we rebuilt with a 3ft plastic hose connected into a jar of gas, two compressions of the hand on the pump arm pulled the gas up lickty split.you do need a good quality pump kit.make sure you are getting the full stroke of the push rod ,The correct 35 pump has a 2/3 piece valve were you cannot replace the seat, not like the 36 that has a valve all in one ,So if your valve seat is worn you will have excessive drain back .there may be a way of repairing by polishing the seat by using something like tooth paste .You could sit the carb over a jar and seal it over the whole think with cling wrap and then watch it over a day or so to see were the gas is going. In my esperance they need a drink more than a skirt's bottle gives,You could set up a clear hose back to the tank to watch the percentage of drain back also .