Available in either black oxide chrome moly or 300-series stainless steel, and your choice of hex or 12-point head. Each ARP intake manifold bolt kit is a must have for cinching your intake manifold in place. Features include a generously flanged 3/8'' bolt head for even loading, and a precision-ground, hardened washer to prevent galling and promote accurate torque readings. 170,000 PSI.