1 Cook the pork roast in the oven on 325 degrees Fahrenheit (163 degrees Celsius). 2  Cooking time will be 35 minutes per lb. (0.45kg) of meat. 3  A pork roast with the bone in will cook faster than a boneless roast.4  It will result in a crispier surface texture with less moisture. Cooking time will be 35 minutes per lb. (0.45kg) of meat. 2  A pork roast with the bone in will cook faster than a boneless roast. 3  It will result in a crispier surface texture with less moisture. 4  This is an ideal method if you want to make gravy.