Preheat your oven to 350 degrees F.
In a large skillet, fry the bacon over medium heat until crispy.
Once done, remove from the skillet and drain on paper towels.
In the same skillet, using the remaining bacon drippings, cook the chopped onion and bell pepper until softened.
Add the ground beef and cook until browned.
Drain any excess fat.
In a large mixing bowl, combine pork and beans, ketchup, brown sugar, mustard, vinegar, salt, and pepper.
Mix everything well.
Crumble the cooked bacon and add it to your mixture along with the cooked beef, onion, and bell pepper.
Stir until all ingredients are well integrated.
Transfer your mixture to a baking dish.
Place the dish into the preheated oven and bake for about 45-50 minutes.
The top should be crisp and bubbly when ready.