Preheat oven to 350° F or 176° C
In a very large mixing bowl, cream butter and cream cheese with mixture on medium speed until creamy and blended.
Add sugar sour cream and vanilla. Mix until fluffy.
Add eggs, one at a time, mixing well after each.
In large mixing bowl, combine flour baking soda, baking powder and salt.
Add gradually to butter cream cheese mixture and blend well
Add blueberries; stir only to distribute. Batter will be a very thick.
Put batter into two greased and floured loaf pans.
Bake for 50 to 60 minutes or until toothpick inserted in center comes out clean
Cool in loaf pans for 10 minutes before removing to wire rack to cool.