1972 Scamp Carb

first thing is to check the float for either being set too high or for being too heavy (saturated with fuel)
I assume you have the little 2bbl carbs (i think they are carter/holley) Last time I had one i hads to drop the float level below what the book called for to get it to run right and get any mileage out of it .

as for the sdvance curve that can only be changed by changing the spring tension on the fly weights under the breaker plate. But on a stock motor there shouldn't be any reason to do that unless they are stuck in the full advance position. Unless I mis understand what you are asking .