Engine › BLACK DIAMOND INTAKE VALVE Image 1 of 1 BLACK DIAMOND INTAKE VALVE $899.99 These materials have proven heat and corrosion resistance properties.A 360-degree anode is used to produce the highest possible grade of hard chrome finish. Quantity: Purchase Added! These materials have proven heat and corrosion resistance properties.A 360-degree anode is used to produce the highest possible grade of hard chrome finish.