What caused this?

It did seem like it was really bogging until I let of the gas. But as I mentioned before it was running fine until that point around 70mph then it just simply didn't want to keep going. I figured if it wasn't getting fuel the car would just quit so I slowley let off the gas. I didn't hear any kind of pinging. But once I got to the end of the strip it was fine. I guess once I let off the gas and slowed down a little fuel was able to flow into the carb easily like any other time. I should have known better to put a stock fuel pump after all the engine work that had been done. A more high performance one is definetly in the works.