2 cents-
I have several Edelbrock 500, 650, and 750 AFB style carbs on everything from a 318, to a 440.
The manual does say a regulator is recommended, but none of mine have one and all run good, pretty much box stock.
The good thing for the OP, is that they are extremely easy to take apart and work on.
None of mine have required any parts, but several have required a good cleaning.
If you're careful, you can even get the top off without tearing the gasket.
The worst part is being careful not to drop and screws or small parts into it !!
Take the top off, look at the float, and clean it out if necessary.