This new choke plate and choke shaft with TWO mounting screws are used on Holley 4 barrel carbs. Choke plate is notched at the bottom and slightly curved at the top. List # 29191A, 2953A, 2953-1A, 2973A , 3255A, 3255-1A, 3410A, 3418-1A, 3668A, 4054A, 4223A, 4296A, 4493A, 4493-1A, 4558A, 4558-1A, 4559, 4578, 4781A, 4781-1A, 4781-2A, 4781-3A, 4781-4A, 4781-5A, 4781-6A, 4781-7A, 4781-8A, 4781-9A, 4781-C & 4788A.