I shoot to maintain my smoker temperature at 225 degrees F and can typically plan about 2 hours of cook time per pound of pork. For example, an 8 pound pork shoulder will take about 16 hours from start to finish. Every cut of meat is a little bit different though, so if you want real control over how your meat is cooking. I’ve had some 8 pound smoked pork butts finish in 12 hours and some 10 pound smoked pork butts take 20 hours to finish.
I recommend a good thermometer to keep track of the internal temperature of the meat. You’ll notice a pattern emerge as you start to smoke pork butts more frequently. You will notice your meat rises in temperature up to about 145 degrees F pretty quickly, then the cooking process will slow dramatically and take hours to increase in temperature from 145 degrees F to 165 degrees F. This phase is called the “Stall” and is completely normal. Don’t panic, just let everything keep cooking and eventually the temperature will start to rise again.