[68 P.O.S.]

It's unlikely your fuel pump went bad since it was replaced and was running well, but there's always that possibility. It could be the carb got gunked up by sitting. Is the engine
stock? Do you know what your timing is set at? How mechanically inclined are you? These trucks really aren't difficult to work on, it's the diagnosing that can be a pain in your rear. Knowing signs and symptoms when something isn't right comes with a little experience and reading through this forum will really help.