Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch baking dish.
Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain.
In a large bowl, combine macaroni, Swiss, mozzarella and Cheddar and stir until cheeses melt. Stir in milk. Season to taste with salt, onion powder, garlic powder, and parsley. Spoon into prepared dish, and dot with margarine.
Bake in preheated oven 50 to 60 minutes, or until top is crunchy.