Like most good fruitcakes, this one will keep for weeks.
Sift together the flour, sugar, cocoa, baking soda and salt. Set aside. Mix together the pecans, candied fruit, raisins and dates.
In a large mixing bowl beat together the eggs, sour cream and vanilla. Add the butter or margarine and then the flour mixture. Beat with the electric mixer at medium speed for 1 minute or by hand until well blended. Add the pecan-fruit mixture and fold in until well distributed. Turn into a generously greased 9-inch tube pan.
Place a shallow pan of hot water on the bottom of the oven. Bake the cake at 300 degrees F for 1-¾ hours, or until cake tester comes out clean. Cool in the pan on a wire rack for 10 minutes.
Wrap tightly in plastic or foil and refrigerate for at least a week before serving.