Cut thin slice off top of garlic head to expose cloves; discard top. Place garlic head on square sheet of foil; drizzle with oil. Wrap garlic loosely with foil. Prick potatoes in several places with fork. Bake potatoes and garlic 1 hour.
Reduce oven temperature to 350 degrees F. Cut small slice off both ends of each potato. Cut potatoes crosswise in half. Scoop out centers, leaving 1/8-inch-thick shells. Place potato flesh in medium bowl; mash. Squeeze garlic out of papery shell into bowl with potatoes. Add sour cream, three-fourths of the VELVEETA and the Parmesan cheese; beat until fluffy. Spoon evenly into shells, mounding filling as necessary to use all the filling; place in shallow baking dish.
Bake 30 min.; top with remaining VELVEETA. Bake an additional 5 min. or until VELVEETA is melted. Sprinkle with bacon.
