AEM high volume fuel rails for the 03-06 Evo 8 & 9 feature a 1/2 inch bore to support fuel flow for applications up to 1,000 horsepower. This large bore also dampens back pressure pulses created by larger injectors and works perfectly with stock injector sizes. AEM included an additional 1/8th NPT port built in for a nitrous input or fuel pressure gauge. The AEM Evo Fuel Rail comes set-up to accept the factory fuel line, or you can purchase the AN Fuel Line Adapter Kit to use custom -6 AN fuel lines.