Preheat oven to 375. Grease and flour a 10 inch tube pan. Sift together flour, soda, baking powder, cinnamon and salt....set aside. In a large mixing bowl, combine oil and sugar. Add eggs one at a time and mix well. Add the flour mixture and beat until smooth. Add nuts and pumpkin and blend until smooth. Pour batter into greased pan. Bake at 375 for 55 minutes test until toothpick comes out clean in the center.In my oven this cake was ready at 45 minutes. Cool in pan for at least 15 to 20 minutes then turn out onto wire rack and cool. Dust with confectioners sugar after cooled.