Preheat the oven to 250 degrees. Butter the inside of a 10-inch, 12-cup Bundt pan. Sprinkle liberally with flour and shake out the excess. Set aside.
In a large mixing bowl, combine the raisins and pecan meats. Sprinkle the 3cups flour and salt over all, and toss with the hands until thoroughly blended. Set aside.
Place the butter in the bowl of an electric mixer. Start beating and gradually add the sugar. Cream the mixture well and add the egg yolks, 1 at a time, beating constantly. Blend the baking soda and warm water and add it to the mixture, beating. Beat in the Grand Marnier. Pour this mixture into the fruit-and-nut mixture and blend together with the hands.
Beat the whites until stiff and fold them in with the hands. Continue folding until the whites are not apparent.
Spoon and scrape the mixture into the prepared pan, smoothing the top with a spatula. Bake 2 or 2¼ hours, or until the cake is puffed above the pan and nicely browned on top. If the cake starts to brown too soon on top, cover with aluminum foil.
Remove the cake from the pan shortly after it is baked. Tapping the bottom of the cake pan with a heavy knife will help loosen it. Store the cake for at least 10 days. If desired, add an occasional sprinkle of Cognac or rum to the cake as it stands. Keep it closely covered and refrigerated until ready to use.