Sift together 2 cups sugar, 2 cups flour, and 1/2 tsp salt.
Mix together in pan, 1/2 cup margarine, 1/2 crisco, 1/4 cup cocoa, and 1 cup water. Bring to boil over high heat. Pour into sifted mixture. Stir.
Now add the 1/2 buttermilk, 1 tsp soda, 1 tsp vanilla, and 2 eggs to entire mixture. Stir well.
Pour into greased and floured 9x13 pan. "Bounce" the pan(not too hard to avoid any sloshes) on the counter or floor, to get out the air bubbles.
Bake at 350 degrees for 30 minutes. When cake is done, toothpick will come out clean from center.
For the ICING: Remove cake from oven and begin to cool. Bring 1/2 cup butter, 1/4 cup cocoa, 6 tblsp milk, and 1 tsp vanilla to boil over high heat. Add 16 oz box of powdered sugar and stir. Remove from heat.
Pour over cake, it will run and cover the cake. Allow cake and icing to cool.