Black DiamondÖ valves are CNC machined from one-piece forgings of EV8 Stainless Steel Black DiamondÖ proprietary multi-stage process reduces friction, and provides superior resistance to corrosion and wear Made in the U.S.A. Must use Kibblewhite« Lightweight Valve Spring Kits when installing Black DiamondÖ Valves.. VALVE EXH 1.610" EVO/TC
