In a small bowl, stir together coconut, brown sugar, and cinnamon.
Measure flour, baking powder, baking soda, and salt into a bowl; mix well.
In a mixing bowl, beat eggs until frothy. Beat in oil and sugar. Blend in sour cream. Add flour mixture, and stir until combined. Put 1/2 of the batter in the bottom of a greased 9 x 5 x 3 inch loaf pan. Sprinkle 1/2 of the cinnamon mixture over batter. Top with remaining batter by putting dabs here and there. Sprinkle remaining cinnamon mixture over top. Cut through batter with a knife to give a swirling, marbled effect.
Bake at 350 degrees F (175 degrees C) for 1 hour. After loaf stands for 10 minutes, remove from pan to cool on rack.
