there may be easier ways but this is what I would do.

1. Replace the fuel pump. Not that hard or expensive.
2. pull the carb to fuel line off and blow it out
3. Open the carb top and check for crap in the bowl. This may give some clues of the condition of the gas tank. Make sure you have a replacement gasket for the carb. You state this is a ebrock carb. They have a lot of bowl for gas so you shouldn't have fuel starvation issues like most due with quadrajets.
4. Drop the fuel tank. Its not as bad it sounds. The less gas you have the better. Pull the sending unit and check the sock condition.
5. Blow out the fuel line from tank to fuel pump.