Hello folks i have a 1981 vette it smokes gray

hello folks i have a 1981 vette it does not seem like it has very much power no acceleration ive set timming new plugs wires are good could it be just the carb or maybe the smog pump it smokes black and gray smoke seems like it is the carb but could it be the computer or the map sensor what would cause the car to idle good but not go fast in gear and smoke oil is clean staryts right up and idles good wont run right any idea is respectable please help thanks