Although it is possible, I don't recommend it because they are different cuts of meat. Pork tenderloin is thinner and longer, and must be cooked over high heat (400 °F) for a shorter period. On the other hand, pork loin is a larger cut and is best slow-roasted or grilled. This is why our stuffed pork loin is first roasted at a high temperature (450 °F) to get a good crust, and then the temperature is lowered to 350 °F to slow-roast it.