*For sour milk, mix 1/2 cup milk with 1 teaspoon vinegar or lemon juice and let sit for a few minutes.
Cream together margarine, oil, and sugar. Add eggs, milk, and vanilla; beat until well blended. In a separate bowl, mix together dry ingredients, then add to creamed mixture. Beat well. Stir in zucchini. Spoon batter into two greased and floured medium loaf pans. Sprinkle chocolate chips over top. Bake at 325 degrees 40 to 50 minutes. Remove from pan and let cool. Sprinkle with confectioners' sugar.