How Long does It Take to Cook a Pork Roast?

Depending on the cut of meat and the weight, will determine how long to cook a pork roast. A loin center roast, weighing 3 to 5 lbs. will take 1 1/2 to 2 1/2 hours in a 325 degree oven. A larger 6 to 8 lb. rib crown roast will take 2 to 3 1/2 hours. The internal temperature should reach 160 to 170 degrees.