318 mopar Carter carb

Is the carb under warrente or new enough to return for replacement.

I would say either the float or needle is the issue.

Or if your pump is supplying way too much pressure
Thats a good point about the fuel pressure I didn't think of that. What kinda of pump are you using op? Mechanical or electric? I think IIRC those carbs only require about 5-7 lbs