Marinate buffalo chuck roast overnight, turning over once to soak both sides.  Remove buffalo chuck roast from marinade and brown both sides over direct heat on grill.  Remove from grill and slow cook (indirect grill) over low heat for 5 hours or until meat thermometer reads 180 degrees F.  Remove roast from foil, baste with Buffalo BBQ Sauce, and continue to cook for 30 minutes, turning roast once and basting every 10 minutes.  For a hickory flavor, add soaked hickory wood chips to the coals for the last half-hour of cooking.