Aeroflow GM LS Header Bolts M8 x 1.25mm, 1.181" (30mm) UHL - Black Finish (AF37-1013)GM LS HEADER BOLTS LONG 12 Point Head, 8740 Material, Sold as a Pack of 12 Part Number: AF37 1013 When installing aftermarketexhaust headers you will need new header bolts, factory exhaust manifold bolts won't work as the flange could be thicker or the original bolts could be damaged. These Aeroflow header bolts are madefrom chrome moly 8740 materialfor high strength properties. They are coated in a black oxide for protection and long lasting