A fully-cooked ham needs to be baked for 10 to 30 minutes per pound depending on the size and cut of the ham, and scalloped potatoes are baked for approximately an hour. They can be baked simultaneously, but a fully-cooked ham generally takes longer to bake than scalloped potatoes.
The oven temperature for both items is normally 350 degrees Fahrenheit, which makes it possible to bake them simultaneously. In order to bake the ham for the appropriate number of minutes, follow the directions on the packaging of the ham or consult a chart of guidelines. It is also good to use a meat thermometer to ensure that the internal temperature of the ham reaches 160 degrees Fahrenheit. The baking time for scalloped potatoes is generally about an hour, so the ham goes into the oven first.