Preheat the oven to 350 degrees. Grind your ham up in the food processor. In a large bowl add the ham, pork, beaten egg, graham cracker crumbs, milk, salt, pepper, and parsley. Combine all the ingredients together.
Take about two tablespoons out and roll into a ball with your hands. Place into a greased 9x13 baking sheet. Bake for 50-60 minutes or until golden and cooked through.
While the ham balls are baking, in a medium-sized pot over medium heat whisk together the ketchup, sugar, mustard, and vinegar. After 2 minutes reduce to a simmer. The last 5 mins of the balls baking, for the sauce over the entire thing. Serve warm.