Chop the bacon; fry crisp, then drain well. Rinse the beans thoroughly and pick through them for anything that should be discarded. Place in a 4 quart saucepan and add enough water to cover the beans by 2 or 3 inches. Over high heat, bring to a boil and boil for 5 minutes. Remove from the heat and leave the beans in the hot water to soak for about an hour. Return to the heat and bring back to the boil. Add the salt; lower the heat to simmer and cook for 45 minutes. Drain the beans and discard the water. Preheat the oven to 275 degrees. Place the partly cooked beans in a heavy casserole, bean pot or Dutch oven. Make a well in the center of the beans and in it place the onion stuck with cloves; cover with the beans. Mix the molasses, 2/3 cup of the brown sugar, the dry mustard and the pepper in a small bowl. Add a cup of water to the mixture; stir to mix well and add to the beans in the pot. Poke the pieces of chopped salt pork into the beans. Cover the beans with the fried bacon pieces and pour a cup of water over all. Cover the pot with a tight-fitting lid and bake for 4 hours. Remove the cover and sprinkle the remaining brown sugar over the bean mixture. Continue to bake, uncovered, for another 45 minutes. Yields 6 generous servings. Serve with steamed brown bread. Note: If the beans seem dry after the 4-hour baking period, add another 1/2 cup of water before adding the final sprinkling of brown sugar. Shortcuts can be taken in making this recipe. In the initial cooking, boil the beans for 15 minutes rather than 5 minutes, and simmer for an hour rather than for 45 minutes. When baking the beans, increase the oven heat to 300 degrees, but watch closely to see that the beans dont dry out too much. Should they become dry as they are baking, simply add a little water. Following these steps will reduce the baking time to 2 1/2 hours.