ARP 1001402 Header Studs With 12-Point Nuts, Chrome Moly Steel With Black Oxide Finish, Set Of 12, For Select Chevrolet Small Block Engines Premium grade stud kit to facilitate installation of exhaust headers Rated at 170,000 PSI, which is considerably stronger than Grade 8 hardware Studs are 3/8" in diameter and have a 1.670 overall length; 12 pieces Manufactured from black oxide finished chrome moly steel Nuts are compact 12-point style, and premium-quality washers are included