Need help with edelbrock 1406 carb

Old thread I know but here is my question: I have now had two big issues with flooding with carter/edelbrock carbs and needed to add regulators; didn’t these cars originally come with Carter’s? Why are fuel pressure issues now such a problem. I had to do this with a new edelbrock. And now sure enough a carter performance afb that I just got has fuel pooring down inside with 9psi pressure. It’s just a mechanical pump. What has changed?