Barbecued Turkey (Eating Your Way Through the Manti Temple Pageant)

For 5 lbs. boneless turkey breast (or chicken)
1 cup oil
2 cups Seven-up
1 c. soy sauce
1/2 T. horseradish
1/2 T. garlic powder

Marinate in a plastic container with a cover.  Combine all ingredients and stir thoroughly making sure of a good mixture.  Marinate for 18 to 24 hours in refrigerator before barbecuing.  Barbecue slowly, do not overcook or burn.  Turn frequently, dipping into barbecue sauce with each turn of the meat.  Cook until meat is white when cut with a knife.