aeroflow performance an steam vent adapters are specifically designed for the ls series engine, these cross over adapters compliment aftermarket intakes and accessories that the factory rigid brazed hard lines will not. the lines are designed to eliminate trapped air and steam from your engine to prevent hot spots and overheating. the adapter o-ring seals converts to -4 an plumbing. featuring fixed or swivel style adapters in dual or single variations allow optimal routing on your application which eliminates the need for t adapters. available in both silver and black anodised options. installing these water cross-over adapters in all 4 corners of the engine have been proven to decrease detonation in number 7 & 8 cylinders especially and are a great improvement over the standard steam vent plumbing. sold individually.