Preheat oven to 350 degrees F. Grease the bottom and 1/2 inch up sides of two 8x4x2-inch loaf pans; set aside. In a large bowl stir together flour, baking powder, cinnamon, and salt. Make a well in center of flour mixture; set aside.
In a medium bowl combine eggs, shredded zucchini, sugar, oil, and vanilla. Add zucchini mixture all at once to flour mixture. Stir just until moistened (batter should be lumpy). If desired, fold in nuts and raisins.
Spoon batter into prepared pans; spread evenly. Bake in the preheated oven about 55 minutes or until a toothpick inserted near centers comes out clean. Cool in pans on a wire rack for 10 minutes. Remove from pans. Cool completely on wire rack. Wrap and store overnight before slicing.