Add the dried chiles to a large saucepan and add enough water to cover them by an inch. Bring to a boil, place lid on pan, turn heat to simmer and steam for 10 minutes. Drain and place in a blender along with the onion, garlic, oregano, cumin and allspice. Puree with 1 cup of water. Set aside.
In a bowl, toss the pork with salt. Preheat oven to 350°F (if baking).
In a large oven safe pot or Dutch oven heat the bacon fat or oil over medium high heat. Add the pork and brown on all sides, in batches if needed. Pour the chili puree over and stir to coat and mix thoroughly.
Cover the pot and either simmer on low for 2 hours or bake in oven at 350°F for 1 1/2 hours. Season to taste with salt if needed.
Serve garnished with cotija cheese crumbles and cilantro along with warm tortillas.
Nutrition info does not include tortillas or cheese due to individual use.