Melt milky way bars with 1 stick of margarine. Stirring constantly with a whisk over low heat until melted and well blended. Set aside. Sift flour, stir baking soda into buttermilk. Set aside. In a large mixing bowl, blend remaining margarine with sugar until blended. Add eggs, one at a time until well blended. Alternate flour and buttermilk mixtured. Beat well after each addition. Add vanilla and milky way mixture. Blend well. Fold in cocunut and nuts. Bake in a slow oven (300 degrees, any higher cake will fall)for 1 hour and 30 minutes or until toothpick inserted into center comes out clean. Cool and serve plain or top with your favorite chocolate buttercream frosting.