Bring 2 cups of beef stock to a low boil on the stove. Meanwhile, wearing gloves, slice open the chile peppers and remove the seeds and ribs. Place the chile peppers in a medium sized bowl. Pour the boiling stock over the chiles, cover the bowl and let it sit for 30 minutes.
While the chiles steam, cube the pork shoulder.
Swirl a generous glug of vegetable oil in the bottom of a large Dutch oven over medium heat. Working in batches, add ⅓ of the cubed pork shoulder, stirring it occasionally for 3-4 minutes just to get the outsides nice and evenly browned. It's okay if it doesn't cook all the way through here. Transfer the browned pork to a bowl and repeat with the remaining two batches of the pork shoulder until all of it is browned and removed from the pan.
Keep the Dutch oven on the heat and add the ground beef. Stir with a wooden spoon to break it up and brown it all over, about 4-5 minutes. Then add the pork back to the Dutch oven with the beef.
Add the remaining 5 cups of beef stock to the Dutch oven along with the bay leaves. Reduce the heat to medium low and let simmer while you finish prepping the rest of the ingredients.
Place garlic, cumin, and oregano in a blender along with the rehydrated chiles and the beef stock they soaked in. Blend on high until a completely smooth, thick, silky sauce forms. If the mixture feels too chunky or has trouble breaking down all the way, you can ladle in some liquid from the Dutch oven.
Pour the chili paste mixture into the Dutch oven with the meat and beef stock. Stir in the tomato paste. Bring to a low simmer and let reduce, uncovered, 3-4 hours. Adjust the heat as needed to maintain a low simmer, you shouldn't see a lot of active bubbling on the surface.Add the beans after about 2 hours. NOTE: As the chili simmers, fat from the meat will pool on the surface. Stir the pot occasionally, but mostly leave it alone. You'll know the chili is done when you stir it and the fat doesn't pool on the surface right away (check it after 5 minutes). This means its has fully incorporated into the chili.
Before serving, add salt and pepper to taste.