Features. Fastener Style - Bolt.. Thread Size - 38-16 in.. Fastener Material - Chromoly.. Fastener Finish - Black oxide.. Fastener Head Style - Hex.. Wrench Diameter - 916 in.. Underhead Length in - 1.000 in.. Fastener Yield Strength psi - 180000 psi.. Washers Included - Yes.Application. Make - Chevrolet.. Year - 1985-1999.. Engine Family - Chevy small block Gen I Chevy big block Mark IV.