I put an Edelbrock performer 650 carb on my 340 Challenger and it would drop on its nose while accelerating especially on cold mornings. I got a metering rod kit and played with them until it performed perfectly except when I was at a light at times it would studder and stall. Foot to the floor was the only way to get it to restart (flooding). Thats when I learned that to much fuel pressure to an Edelbrock carb will push past the floats and flood. I put a pressure regulator in line and tweeked it down from 8 psi to the recommended 5.5 psi of pressure and never had another problem again.
Hope it helps.
