Preheat oven to 325 degrees F (165 degrees C). Lightly grease two 8x4 inch loaf pans.
In a medium bowl, combine cream cheese, 1/2 cup sugar, 1 tablespoon flour, 1 egg and orange zest; beat until smooth. Set aside. Sift together 1 2/3 cup flour, baking soda, salt, cinnamon, cloves and pumpkin pie spice; set aside
Place pumpkin, vegetable oil, 2 eggs and 1 1/2 cup sugar in a large bowl; beat well. Stir the pumpkin mixture into the flour mixture just until combined. Fold in the pecans if desired. Pour 1/2 of the pumpkin batter into the loaf pans. Spoon cream cheese mixture on top of this layer and then pour on the remaining batter.
Bake in preheated oven for 60 to 70 minutes, or until a toothpick inserted into center of the loaf comes out clean. Cool bread in pans for 10 minutes before removing to a wire rack to cool completely.