Cheesy Red Potato and Ham Casserole

4 pounds red potatoes, diced
1 (16 ounce) container sour cream
1 cup fat free evaporated milk
2 cups shredded Cheddar cheese
1/4 cup chopped green onion
2 lbs. cooked, chopped ham salt and pepper to taste
1 1/2 cups flavored bread crumbs
1/4 cup melted margarine
Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 9×13 inch baking dish. Place potatoes in a large pot of water, and bring to a boil. Boil until slightly tender, about 12 minutes. Drain, and transfer to a large bowl. Mix sour cream, evaporated milk, Cheddar cheese, ham, salt and pepper with the potatoes. Spread mixture in the prepared baking dish. Sprinkle with bread crumbs, and drizzle with margarine. Top with green onions Bake 30 minutes in the preheated oven.