This is one set of header/manifold bolts for all LS engines. Compatible with all GM LS & LT (Gen III, IV, & V) series engines 1997 and newer These 269 Motorsports bolts are custom made locally for us. Grade 10.9 Bolts are clear zinc coated steel, Grade 10.9 Package Includes: 12pcs - M8-25mm length (enough bolts to install passenger and driver side headers on one vehicle) Torque Spec for M8 exhaust bolts is 18 ft-lb