Hi Dave,
What type of carburetor? With the Carter YF I have had a few float issues, but they don't mimic what you described. What happens with mine is that if the fuel dries out in the float bowl (allowing the float to drop to the lowest point) the 3 piece spring-loaded needle valve will stick and then when I start the engine (I use a 3~3.5 psi electric pump for everything) it will flood.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end