This kit is a Grade 8 Stainless Steel ARP (American Racing Products) bellhousing bolt kit for the GM cars with an Aluminum Bell Housing or transmission. This kit will fit the Turbo 350, 400, and PowerGlide transmissions. 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 6 point head and a .625 diameter flange for easier access in the tight spots. This kit also includes extra thick heavy duty stainless washers.