Question:

The engine bangs out really bad as if it's not getting enough fuel. I don't know the history on this engine, it has been rebuilt, not sure if the cam in stock, it does have headers on it. Is it possible that I need even larger mains?

Answer:

A new ignition control module fixed it!!

Pops Thru the Carburetor When Accelerating

I won't address the possibility of a bad valve. This condition is often caused by a lean condition in the carburetor.

• Main jets may be too small. Pull a spark plug or 2 and look at the color. Should be gray, tan, light brown. White indicates too lean. Try increasing jet size by .002
• Check that the accelerator pump is working. With the engine off look down the carburetor and pump the gas. You should see 2 good squirts of gas coming out of the venturi. If there isn't a strong squirt then the main discharge check may be leaking, or not sealing. Tap the check ball lightly to form a good seat. Also see if the venturi gasket is sitting flat. They sometimes need to be trimmed.
• Spray carburetor cleaner through all of the passages going to the venturi to make sure they are not plugged.
• Check the float bowl level. It should be set to specifications. Don't fudge the setting. That will just cause another problem.
• Look for vacuum leaks around the base of the carburetor, vacuum lines and intake manifold.
• Test the fuel pump pressure for 4.5 lbs prox.