This spark plug provides consistent starts with superior fouling resistance. Dependable performance. Replaces Champion CJ6, CJ8, RCJ6, RCJ8, 5843. Replaces NGK BM6A, BM6Y, BM7A, BM7Y, BMR6A, BMR7A. Replaces Autolite 254, 255. It has 14-mm thread size reach hex 3/8-inch by 13/16-inch. Measures 2-3/5-inch length by 6-3/5-inch width by 8/9-inch height.