Preheat the oven to 325°F and set an oven rack in the middle position. Generously grease two 8 x 4-inch loaf pans with butter and dust with flour, or use a baking spray with flour in it, such as Pam with Flour or Baker's Joy.
Sift flour, salt, baking soda, baking powder, clove, cinnamon, and nutmeg into a medium bowl. Set aside.
Using an electric mixer, beat the butter and sugar on medium speed until just blended. It will be grainy not creamy. Add the eggs one at a time, beating well after each addition. Continue beating until very light and fluffy, a few minutes. Beat in the pumpkin. The mixture might look grainy and curdled at this point -- not to worry, flour to the rescue in the next step.
Add the flour mixture and mix on low speed until combined. Do not overmix.
Turn the batter into the prepared pans, dividing evenly, and bake for 65 – 75 minutes, or until a cake tester inserted into the center comes out clean. Start checking at 55 min. Let the loaves cool in the pans for about 10 minutes, then turn out onto a wire rack to cool completely.