Designed for stock or Edelbrock manifolds, these Fuel Rails are fully CNC machined from aluminum extrusions, polished then hard anodized for use with racing fuels (including methanol). The 5/8'' i.d. fuel passage features a flow-through design with 8 AN o-ring threads on both ends. These Edelbrock Fuel Rails include a fuel regulator mounting at the end of the rail that can be used with stock or aftermarket regulators and two auxiliary 1/8'' NPT ports for pressure gauge, nitrous system fuel supply, etc. All hardware is included for an easy installation.