79 Subaru GF project car. Intermittently car will die and no fuel is observed in float chamber. Also at times can turn off and then restart and all available fuel in float chamber is consumed and stalls. Although fuel pump is heard, removal of supply line at carb and no fuel. Have 11.40-11.70 volts going to fuel pump. Allow car to sit for 5-10 minutes and fuel available in carb and runs until observed again? Is there a filter in gas tank that could be progressively clogging and then "releasing" contaminants or fuel pump bad?