I was having problems with my 68 Mustang (289 w/2V Carb) stalling when accelerating from a stop. It finally got to the point where I decided to clean the carb, replace the diaphragm in the accelerator pump, and replace anything else that looked suspect. I don't have any experience with carbs, but I would call the fuel bowl dirty. I cleaned that out and replaced most of the gaskets on the carb. The check *****, float, etc. all looked fine so I did not replace these items. The car still stalled if I floored it from a stop and there was a little dip in power before it caught when I floored it from a cruising speed of 40-45 mph. I pulled the air cleaner back off and looked down the throat of the carb with a flashlight while moving the accelerator rod, which activated the accelerator pump as well. The engine was not running. I could see fuel on the driver's side throttle plate, but couldn't say that I saw how it got there. Could this mean that the accelerator is only providing fuel to the driver's side of the carb rather than both sides? Am I just seeing fuel supplied by the main jets (not from the accelerator pump) and is only one of them working? Should I be able to see a fine stream of fuel if the accelerator pump is working properly? Any other ideas as to what could be causing the car to stall under heavy acceleration?

P.S. I recently replaced the tank and fuel filter as well.

 

When you stomp on it do you move at all before it stalls? Its possible that its not a lean condition but if your float level is too high you're flooding the engine if fuel is coming out of the vent.