In heavy Dutch oven, heat oil and brown meat on all sides.
Combine vinegar, bourbon, brown sugar, ketchup, soy sauce and garlic; pour over roast. Bring to a boil; reduce heat. Cover and simmer 1 hour for medium degree of doneness, or until tender.
Remove roast to a platter; cover with foil and let rest 10-15 minutes. Mix cornstarch with water. Bring pan juices to a boil and quickly whisk in cornstarch paste. Boil for two minutes.
Slice roast and serve warm bourbon sauce.