Adjustable billet by-pass return style fuel pressure regulator 6AN Boost Reference - 1:1

PART# 12-880



Holley Billet Fuel Pressure Regulators are part of a complete line of fuel system products from Holley. They are precision machined from 6061-T6 billet aluminum for strength and durability. These regulators are adjustable from 4-65 psi and will handle both carbureted and EFI applications. A second pressure spring is included allowing you to increase the fuel pressure range up to 65 psi for EFI systems. They are offered with two port sizes, 3/8" NPT or 6AN to adapt to your new or existing fuel lines. So, if you are currently running a carbureted system but plan to upgrade to EFI in the future, these regulators will have you covered either way.



  • Adjustable from 4-65 psi for precise fuel pressure adjustments
  • Constructed of billet aluminum with a black anodized base and a clear anodized top for good looks
  • Used in systems with a return line back to the tank
  • (1) 6AN O-ring Inlet; (1) 6AN O-ring Outlet; and (1) 6AN O-ring
  • Includes fitting for manifold reference
  • Includes an 1/8 NPT gauge port
  • Boost Reference - 1:1
  • The 4-15 psi carbureted spring comes installed in the regulator


Pressure Range (psi): 4-65

Regulator Style: Return

Regulator Location: Inline

Boost/Vacuum Reference Port: Yes

Boost/Vacuum Rise Ratio: 1:1

Gauge Port: Yes

Mounting Bracket Included: Yes

Fittings Included: No

Rebuildable: Yes

Inlet Quantity: One

Inlet Attachment: Female threads

Inlet Size: -6 AN O-ring

Outlet Quantity: One

Outlet Attachment: Female threads

Outlet Size: -6 AN O-ring

Return Attachment: Female threads

Return Fitting Size: -6 AN O-ring

Regulator Material: Billet aluminum

Regulator Finish: Black/Clear anodized

Quantity: Sold individually.


Part of Holley's complete line of fuel system products, Holley HP billet fuel pressure regulators are available in a variety of configurations for carbureted or fuel injected engines. Some versions are even adaptable to either carburetors or EFI. They allow you to upgrade a carbureted system to EFI without replacing the fuel pressure regulator. 

All HP billet fuel pressure regulators feature a 2-port design, provide for precise fuel pressure adjustments, and are available in your choice of demand (no return line) or by-pass (with a return line) styles. Depending on the model, they are for use only with electric fuel pumps, or with either mechanical or electric pumps. Designed for street/strip applications, they are CNC-machined from 6061-T6 billet aluminum for strength and have bright dip anodized black bodies with clear dip anodized tops for corrosion resistance and good looks. Whatever your fuel system needs, Holley has you covered.

Depending on model, features may include:

* Adjustable from 4 to 65 psi for use with EFI or carburetors
* 4.5 to 9 psi adjustment range for use with carburetors only
* EFI-only models are adjustable from 15 to 65 psi
* Two port sizes available, 3/8 in. NPT or -6 AN inlet/outlet and return (where applicable)
* Fitting for manifold reference
* 1/8 in. NPT gauge port
* Boost reference--1:1