Combine ricotta cheese, 8 oz. mozzarella cheese and eggs together. Mix well.Spoon cheese mixture into the cooked pasta shells. Place in greased 9 X 13 pan. Top with remaining cheese. Sprinkle cooked Italian sausage over the cheese. Top with spaghetti sauce. Sprinkle parmesan cheese over sauce. Bake covered with foil for 30 minutes at 350 degrees.Uncover and cook the remaining 15 minutes.