Preheat oven to 325°F
Grease loaf pans with butter or cooking spray, then dust with flour.
In a mixing bowl, combine the flour, salt, baking soda, baking powder, cloves, cinnamon, nutmeg, and allspice. Whisk or stir to combine.
In mixer, beat the butter and sugar until blended into a sandy consistency.
Add the eggs to the butter and sugar mixture, one at a time, beating to combine until the mixture is fluffy.
Add the pumpkin and continue to beat for 6-8 minutes, to combine thoroughly.
Add the flour and spice mixture to the wet mixture, continuing to beat until combined.
Divide the batter into two loaf pans.
Bake until a skewer/knife/cake tester comes out clean, about 60-70 minutes. Larger loaf pans will cook slightly faster and result in thinner, wider loaves.
Remove from oven and let cool until the loaves can be removed without falling apart, about 15-20 minutes.