As a kid, I had a 69 340 in a Dart, somehow the stock Carter 650 could never be improved upon. Of course, that was in the 70's and the technology changed dramatically.
I did have a Holley 750 on it at one point in time, but the Carter 650 made that engine "light-up".
Too much fuel?
Have you had the car for a while? What was the previous carb and was it better?
Perhaps is not a carb issue and the timing could be advanced.
Chrysler had a pretty good "performance sense" and cars were fast right out of the dealerships.