1. Place bacon in a large, deep skillet. Cook over medium high heat until evenly brown. Drain, crumble and set aside.
2. In a large bowl, combine the bacon, cream cheese, Cheddar cheese and salad dressing. Mix together well and form into a ball.
3. In a shallow dish, mix together the parsley and chopped walnuts. Roll cheese ball in mixture to coat. Refrigerate until chilled.