Preheat oven 350 degrees F. Grease and flour 9x11 pan. Combine sugar, flour, and baking soda; mix together. Add pineapple with juice (don't drain) mix until moistened. Add coconut and walnuts. Mix well, batter will be stiff.
Pour batter into prepared pan.
Bake in preheated oven for 45-50 minutes or until lightly golden of toothpick inserted comes out clean. Cool. Top with cool Whip.