This kit is a Grade 8 Stainless Steel ARP (American Racing Products) fan pulley bolt kit for the Mopar V-8 engines. These bolts are for an engine with a steel fan and no fan spacer. They are not only good looking, and don't rust, but they are super strong for your high horsepower needs and have a polished finish. These bolts have a tensile strength of 170,000 psi. They have a 3/8 inch 12 point head and a .625 diameter flange for easier access in the tight spots.