Carb vaccum leak?

another thing, check for vaccum leaks around all of your throttle shafts, Fire it up and let it idle till its fully warmed up, then take some wd-40 or some carburetor cleaner and just spraye quick bursts of it around your throttle shafts if the idle increases there's a vaccum leak.
Also spray around the base of the carburetor, and dont over tighten the carter or edelbrock carbs they can crack verfy easily and cause vaccum leaks.