Grease or line two 8x4 inch (20 x 10 cm) loaf pans with parchment paper.
In a large bowl combine flours, cocoa, baking powder, baking soda, cinnamon and salt.
Stir in chocolate chips and set aside.
In a medium bowl, beat together sugar, eggs, sour cream, oil and vanilla.
Stir in grated zucchini.
Add wet ingredients to dry ingredients. Stir just until combined.
Pour into prepared pans (batter will be thick).
Bake for 50 minutes.
Cool in pans for 5 minutes and then on a wire cooling rack.
Notes
* Replace whole wheat with 1 cup all purpose flour if you prefer.This loaf freezes very well once cooled. Makes 2 loavesNutrient content is shown for 1 full loaf.