This an exhaust manifold kit for mounting stock manifolds to the heads on your Small Block Ford V-8 engine. These bolts are grade 8 stainless steel and 8 of the bolts are 1 inch long and the other 8 are 2 1/4 inches long. These are ARP bolts and come with a polished finish. We also include extra thick flat washers. Please verify the fit to your engine before ordering. These bolts are much stronger than the stock bolts and are rated at 170,000 psi.