In a small bowl, combine all ingredients but roast. Mix well! Pierce roast sevral times with fork and place in a non-metal bowl and pour marinade over roast. Marinate 6-8 hours or overnight in refrigerator, turning twice.
Preheat oven to 350�F. Place roast in shallow roasting pan and cover with aluminum foil in a tent fashion. Place roast on middle rack and back for 1 1/2 hours. You can baste it every 45 minutes with leftover marinade. Let stand for 15 minutes before slicing.