To maintain a reputation for "zero defects", ensure optimum quality control, and produce fasteners of exceptionally high quality, ARP controls all aspects of the manufacturing process, performing all operations in-house where they can be closely monitored. ARP takes extraordinary steps to produce the very finest products of their kind on the market today. Now you can help prevent intake manifold leaks with ARPs quality fasteners. These conventional hex style bolts are manufactured from chrome moly steel with a black oxide finish, and are rated at 170,000 psi. They are precision machined with rolled threads, for optimum thread engagement and to prevent galling, while promoting more consistent torque loading. The wide underhead flange and companion washers provide even load distribution, facilitating optimum sealing of gasket surfaces. This kit is specially designed for select Chevrolet applications (Big Block, 396-454 cid, 1.250" under head length).