Preheat oven to 350°F. Spray a 9x5-inch loaf pan with cooking spray or line with parchment paper.
In a medium bowl, add flour, baking powder, baking soda, salt, cinnamon, nutmeg, ginger, and cloves. Combine with a whisk and set aside.
In a large bowl, combine the sugar, oil, eggs, vanilla, molasses, pumpkin puree, and orange juice with a hand mixer on medium-low.
Add the dry ingredients to the wet ingredients. Mix on low to medium-low just until the ingredients are combined.
Remove half of the batter to a medium bowl. Add cocoa powder and fold to combine.
To the loaf pan add alternating scoops of pumpkin batter and chocolate pumpkin batter. Continue until all of both batters are in the pan.
Use a skewer or knife to gently swirl the batters together in an s-shaped pattern.
Bake for 80 minutes, or until a toothpick comes out with crumbs, but no wet batter. Cool and serve.