Billet aluminum fuel rails for use on Gen-V LT1 Atomic AirForce intake manifolds. Fits manifold part numbers 2700, 27003 and 27004. MSD's new Atomic EFI billet fuel rails enhance the great looks of your Atomic AirForce intake manifold. Available as rails only, or as complete kits that include all necessary plumbing, these fuel rails are a perfect addition to your engine bay. The bright dip, black anodized finish with laser etched logos will look great for years. MSD Atomic fuel rails feature a 5/8" diameter fuel passage that provides the flow capacity necessary to fuel high horsepower applications making them the perfect match for your Atomic AirForce intake manifold. • If using tall EV1/Bosch style injectors on LS7 or LT applications, there may be interference on low hood applications as on Corvette and similar. • 1999-2004 applications utilizing a factory supply and return fuel line will require the addition of a fuel pressure regulator when installing MSD fuel rails. • P/N 534-211 - Adapter kit, required when directly connecting Atomic fuel rails to GM factory fuel line quick-connect. Includes (1) 3/4-16 O-ring port plug and (1) -6 to GM quick connect adapter. • SPECIAL TOOL REQUIRED: GM 3/8" Quick-Connect Release Tool to disconnect the factory fuel line (these are inexpensive and available at the local auto parts store). • Fuel rails are machined to accept large -8 (3/4 -16) O-ring fittings (sold separately) - Earl's P/N AT9850008ERL - 4 required.