Preheat oven to 325 degrees F. Combine pepper, salt, chili powder, cumin and oregano in a bowl. Rub the roast with this spice mixture. Heat the olive oil in skillet over high heat. Place the roast in the skillet and darkly sear on all sides. Place in the oven, first transferring to a roasting pan if your skillet is not ovenproof. Roast to desired doneness, about 60-75 minutes should yield it rare to medium rare.
Transfer roast to a plate and rest 10 minutes. Remove fat from the drippings in the pan. Place pan on the stovetop over medium-high heat. Add the barbecue sauce and stock and bring to a simmer. Thinly slice beef and pile on buns. Spoon the sauce into small dipping bowls. Create a red-eye by dropping a spoonful of ketchup or steak sauce in the centre.