engine chuggin

as far as im concerned its a stock motor as when i bought the car the guy didnt tell me to much about it just that it was stock and from a 68 p/u. i threw a mopar m1 intake stock exhaust manifold dual exhaust the carb is a 4776 holley 600. as for timing im not sure wat its at as i power timed it when it had a 2bbl dist is a vac adv mopar