Preheat oven to 350°F. Butter 2 loaf pans and place a piece of parchment paper in the bottom of each (cut to size) and spread it with butter. Flour each so they are well coated.
Sift flours, baking powder, baking soda, salt and spices in a medium bowl.
Grate zucchini and carrots in the food processor with the grating blade. (or you can do this with a hand grater as well. (Reserve any extra carrots or zucchini to mix into a casserole or soup later - you can freeze the extra if you have any)
Combine zucchini, carrots, sugars, eggs, oil, juice and zest in a large bowl. Mix well.
Add the flour mixture to the zucchini and carrot mixture and stir just until it is mixed together, being careful not to over mix. (You may still have a few lumps in the batter and this is ok!)
Mix in the nuts and raisins, if desired
Divide the batter between the 2 pans.
Place in the center of the preheated oven ad bake for approximately 1 hour (check after 50 minutes) Test with a toothpick - it should come out clean from the center.
Remove pans and place on a metal rack and let cook for 10 minutes. Then remove the bread from the pans and allow to cool completely.
These can be frozen for up to 4 months. Wrap tightly in plastic wrap or another wrap that seals well.