Preheat oven to 325 degrees. Grease a 9by 13by 2-inch pan. Sift together flour, cocoa, baking soda and salt in a large mixing bowl. Set aside. In a separate bowl, cream the butter, vegetable oil and sugar, beating until the mixture is light and fluffy. Beat in the eggs, one at a time. Next, add the vanilla and chile powder. Mix in the dry ingredients that have been set aside, alternating with the buttermilk. Stir in the zucchini. Pour the batter into the prepared pan. Sprinkle the top of the cake with the chocolate chips and walnuts. Bake for about 55 minutes or until a toothpick in center comes out clean. Cool cake in the pan on a wire rack. From Sweet heat: Spicy Desserts (& More!) For Chile Lovers (c) The Arizona Republic (6/5/96) Hunt and pecked by John Blackwell, Taylorsville, Utah, U.S.A., scooter@xmission.com.