Lower oven rack to a low position. Heat oven to 350°F. Grease the bottom of 1 loaf pan, 9x5x3 inches.
Puree mango and raisins, and set aside.
Beat the sugar and the butter in a large bowl. Afterward, stir in the eggs until well blended. Then add buttermilk and vanilla and beat until the mixture is smooth. Next, stir in the flour, baking soda, and salt-just until moistened. Stir in mango mixture. Pour batter into pan.
Bake the loaf for about 1 1/4 hours, or until a toothpick inserted in the center comes out clean—cool 10 minutes. Then remove from pan to a wire rack. Allow loaf to cool completely before slicing. Wrap tightly and store at room temperature up to 4 days, or refrigerate for up to 10 days.