1-3/4 in. Tube Dia. 3 in. Coll. FULL LENGTH Design These LONG-TUBE headers fit a variety of BB Chevy (396-454) powered 1967-77 Chevy passenger cars. Model like, 1967-69 Camaros, 64-77 Chevelles and El Caminos, 68-74 Novas, and 1965-70 Belair, Impala and Biscayne models. The smooth 1-3/4 in tube design provides ample exhaust flow to let your 396-454 Chevy engine breathe easy, and produce maximum horsepower and torque.