Hi, I am a professional certified mechanic, with an engineering background, and 35+ years experience. I will do my best to assist you. Also keep in mind I don't know if you are a pro or a novice, so feel free to add any additional info at any time.
383 strokers are a nice setup, I have one in my 95 Impala SS. Have you checked the valve clearance since it started acting up. If it was mine I would pull the valve covers and check the springs and valve clearance. I would also pull a spark plug to see if any fouling of the plugs is occurring. You would be looking for a clack carbon deposit. If the carb is a little too rich, it can start a slow process where the plugs foul from the extra gas. Once this happens it will loose power and start popping. The carbs power valve can start leaking, or a needle and seat can start leaking to cause this type of problem even if it is jetted perfectly.
Beyond all this check out the distributor cap, rotor, and ignition timing. Look at the spark to make sure it is crisp and blue. Odds are it is a small tuning problem, still you need to keep an eye out for anything unusual. Go over all of this and if you have any more questions at all, I am here to help. Good luck with it, have a great day, and Thanks for using Just Answer.
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