273 carb probs!!!
these charts are very conservative but there good for very flexible running. good economy throttle response and decent power. when i type response i don't mean power i mean no dead spots smooth flexible operation. just a reminder nascar truck division uses 390 carb and make huge power. 600 range. (although they would go bigger if the rules allowed them) they make big power because those engines are highly refined. but the point is you don't need large to make good power.