For a medium-well roast, cook a pork butt roast at 275 degrees Fahrenheit. The pork butt roast should reach an internal temperature of 155 F.
Calculate the overall cooking time by the weight of the roast. For a roast weighing between 3 and 6 pounds, cook for 55 to 85 minutes per pound. For example, a 5-pound roast should be in the oven at 275 F for four hours and 30 minutes to seven hours.
Take the temperature at the thickest point of the roast. Once the roast has reached 155 F, remove it from the oven and allow it to rest for three minutes before carving.