In medium bowl, mix 1 1/2 cups flour, the cocoa, baking soda and salt; set aside. In large bowl, beat oil and granulated sugar with electric mixer on medium speed. Add eggs, one at a time, beating well after each addition. Beat in vanilla. On low speed, alternately add flour mixture, about one-third at a time, and 3/4 cup milk, about half at a time, beating just until blended.