I'd also look into installing a primary gas filter,a big one down by the tank,and use the little one on the carb as a secondary filter. CarQuest has a fuel filter that fits a remote oil filter base (Ford size). If ya plug THAT up you need a new tank.
Seems like these old trucks get a lot of crud in the gas tanks,and the more you filter the gas,the less crud gets to the float bowl.
Speed