Carb question stock 340

Back when I had a 351 clevland in the early eighties I tried a few carbs to see how they went. A 750 double pumper went alright until it drained the tank in a few days. I filled the tank again and it used about twice the amount of fuel than the std carb. I settled on a carter afb and it was better on fuel than the std carb but these clevos were thirsty sons of bitches and didnt perform that well compared to my 340 charger before it.