Heat oven to 350°F. Grease bottom only of 2 (8x4-inch) loaf pans; set aside.
Combine flour, cinnamon, salt, baking soda, baking powder, cloves and nutmeg in bowl; set aside.
Combine sugar, butter, eggs and vanilla in another bowl. Beat at medium speed, scraping bowl often, until smooth. Add flour mixture; beat at low speed until well mixed. (Mixture will be very thick.) Stir in zucchini and walnuts.
Spread batter into prepared pans. Bake 55-65 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; remove from pans. Cool completely.