I have an old dump truck with a 391 and a Holley 4160. It has the "List 1850-3" number on it. I recently rebuilt it and had it running. Now I can not get it to start without pumping the pedal about 15 times first. It starts & runs smooth for about 30 seconds before it bogs & dies. The first step I took was to change the fuel filter. I thought maybe it was not allowing enough flow and starving the carb for fuel. This had no effect on the start, bog & die. Next I thought maybe it was the fuel pump. I pumped the pedal, started, and then let it bog & die. As soon as it died, I took out the screw in the side of the bowl. The fuel lightly trickled out, so it had the right amount of fuel in the bowl when it died. I'm now thinking it's in the idle portion of the carb. Where do I start troubleshooting it now? Thanks, Wayne