This kit is a Grade 8 Stainless Steel ARP (American Racing Products) crank pulley bolt & washer kit for the Chevy V-8 engines. These bolts have a fine thread on them. If you need a coarse thread for your aftermarket balancer, just let us know. We have these in stock also. These are not only good looking, and don’t rust, but they are super strong and have a polished finish. These bolts have a tensile strength of 170,000 psi. They have a 12 point head and a .625 diameter flange for easier access in the tight spots. This kit also includes AN stainless washers.