Combine beef broth, soy sauce, garlic, cumin, chili powder, and ground red pepper in resealable plastic food storage bag; knead bag to combine. Add beef and seal. Refrigerate up to 24 hours, turning occasionally.
Remove beef from marinade; discard remaining marinade. Grill beef over hot coals 7 minutes per side or until desired doneness. Grill bell peppers, 7 to 10 minutes or until tneder, turning once.
Slice beef and serve with bell peppers, tortillas, sour cream, and salsa.