1. Sprinkle salt and pepper all over beef and pork. Place large pot over medium-high heat; when hot, add olive oil and brown meat. Remove meat to a platter. Turning heat under pot to medium, add onions, cook for 3 minutes, stirring. Add garlic, and cook for 2 minutes longer. Add tomato paste and stir. Cook until it absorbs fat in the pan. Add oregano, basil, red pepper flakes, kosher salt and bay leaf, stir to combine.
2. Add cans of tomatoes and tomato sauce, then 4 1/2 C of water. Stir in sugar, parsley, and pepperoncini. Return meat to the pot with their juices. Bring sauce to a gentle boil. Turn heat down to simmer, partly cover and let simmer for 2 1/2 hours of more, stirring regularly.
3. About 20 minutes before serving, add meatballs to pot. Boil spaghetti according to package directions. Drain, return spaghetti to pan and add 3 C of sauce. Toss pasta in pan to cover with sauce, and place on large platter. Place 2 more C of sauce on pasta , add meatballs to the meal and enjoy.