1969 Dodge Dart Engine Stutter

get alternator checked, could be a bad voltage regulator, both are pretty cheap in the scheme of things. I dont think the car would stutter with 12v as the coil routinely runs on 9. What carb? Backfires can damage certain carbs (Holley 2300,4150-60) Carb may be loading up with fuel. Check the carb venturis when its idling (careful doing this) if you see fuel dribbling out any orifice in quantity, your needle/seat is contaminated. tap on the carb with a hammer and sometimes that frees is up.