My 390 is surging and stumbles on acceleration from a dead stop. The engine is bone stock and has a holley 4160 on it. I also noticed at times the fuel filter has little to no gas in it when the engine is running. Other times it does. It has a new fuel pump on it. Any suggestions where I might start my search for the problem?

 

There are several things to look at. The carb, vacuum leak and the accelerator pump.
Base timing and verify that the vacuum advance is working.

 

EGR valve or manifold ?