Holley EFI LS Hi-Flow Fuel Rail Kit – LS1, LS2, LS3, LS6 & L99 Intakes
534-209
The Holley EFI LS Hi-Flow Fuel Rail Kit is designed for GM LS engines using compatible LS1, LS2, LS3, LS6, and L99 factory-style intake manifolds. Manufactured by Holley EFI, these billet aluminum fuel rails use a large 5/8" internal fuel passage to support the increased fuel demand of higher-horsepower naturally aspirated, boosted, and performance LS combinations.
Each rail is machined for -8AN / 3/4"-16 O-ring fittings and includes -6AN adapters, giving builders flexibility when plumbing pumps, regulators, feed lines, and return-style EFI systems. The black anodized finish, laser-etched Holley EFI logo, included mounting brackets, and installation hardware make this a clean upgrade for LS swaps, race cars, off-road builds, and street performance applications using compatible factory intake manifolds.
Includes:
- (2) Holley EFI Hi-Flow Fuel Rails
- (4) -6AN to 3/4"-16 O-Ring Adapters
- Fuel Rail Mounting Brackets
- Required Mounting Hardware
- Required Seals
Note: Fuel injectors, fuel pressure regulator, fuel lines, and additional fuel system fittings are not included.
Specifications
| Specification | Details |
|---|---|
| Manufacturer | Holley EFI |
| Part Number | 534-209 |
| Product Type | EFI Fuel Rail Kit |
| Engine Family | GM LS |
| Compatible Intake Families | LS1, LS2, LS3, LS6 & L99 Factory Intakes |
| Fuel Injection Type | Port Injection |
| Fuel System Type | EFI |
| Material | Aluminum |
| Finish | Bright-Dip Black Anodized |
| Fuel Passage Diameter | 5/8" |
| Rail Port Size | 3/4"-16 O-Ring / -8AN Compatible |
| Included Adapters | (4) -6AN to 3/4"-16 O-Ring |
| Fittings Included | -6AN Adapter Fittings Included |
| Fuel Injectors Included | No |
| Gaskets / Seals Included | Yes |
| Grade | Performance |
| Emission Code | 5 |
Fitment
Designed for compatible GM LS engines using LS1, LS2, LS3, LS6, and L99 factory intake manifolds.
| Engine Size | Displacement |
|---|---|
| 4.8L V8 | 294 CID |
| 5.3L V8 | 325 CID |
| 5.7L V8 | 346 CID |
| 6.0L V8 | 364 CID |
| 6.2L V8 | 376 CID |
| 7.0L V8 | 427 CID |
Fitment Notes
- Intended for compatible LS1, LS2, LS3, LS6, and L99 factory intake manifold applications.
- Engine displacement alone does not guarantee fitment. Verify intake manifold style, injector spacing, and injector configuration before ordering.
- The rails are machined for -8AN / 3/4"-16 O-ring fittings and include four -6AN adapters.
- Fuel injectors, regulator, supply hose, return hose, and additional plumbing are sold separately.
- Fuel pump capacity, injector size, regulator capacity, line size, and fuel type should be matched as a complete system.
FAQ
1. What is the benefit of the 5/8" internal fuel passage?
The larger fuel passage increases available fuel volume through the rail, helping support engines with higher fuel demand than a factory-style fuel rail was designed to handle.
2. How is this kit different from Holley's LS truck intake fuel rails?
This kit is designed around compatible LS1, LS2, LS3, LS6, and L99 factory intake manifolds. Holley's truck-intake fuel rail kit is intended for LS truck-style intake manifolds, so selecting the correct rail kit depends primarily on the intake manifold being used.
3. Can I use -8AN fuel lines with these rails?
Yes. The rails are machined with 3/4"-16 O-ring ports compatible with -8AN fittings. The kit also includes four -6AN adapters for builders using smaller fuel line plumbing.
4. Are these fuel rails a good upgrade for boosted LS engines?
They can be. The increased rail volume and AN-style plumbing options make them well suited to higher-flow EFI systems, including naturally aspirated, supercharged, and turbocharged LS combinations. Pump, injector, regulator, and line capacity must still be matched to the engine's total fuel demand.
5. Are fuel injectors included with the kit?
No. Fuel injectors are sold separately so they can be sized for the engine's horsepower, fuel type, boost level, and intended use.
