Holley 12-880 Adjustable Billet Fuel By-pass Regulator-6AN SKU: 6669

Holley Adjustable Billet Fuel Bypass Regulator | 6AN Fittings | #12-880

Engineered for performance and precision, the Holley Adjustable Billet Fuel Bypass Regulator (#12-880) is designed to deliver precise fuel pressure control for both carbureted and EFI systems. Precision-machined from 6061-T6 billet aluminum, it features a sleek black anodized base and a clear anodized top for a professional finish that’s built to last. This regulator is adjustable from 4 to 65 PSI, with a second spring included for EFI setups requiring higher pressure. Ideal for return-style fuel systems, the Holley #12-880 ensures your engine receives consistent, regulated fuel—whether you're on the track or the trail.

For a more complete fuel bypass system, check out our WH Adjustable Fuel Bypass Regulator Kit.

• Wide Pressure Adjustment Range: Adjustable from 4–65 PSI to support both carbureted and EFI applications.

• Billet Aluminum Construction: Machined from 6061-T6 aluminum with a durable anodized finish for lasting strength and style.

• Return-Style System Use: Designed for systems using a return line back to the tank.

• Fittings & Ports: Includes (1) 6AN O-ring inlet, (1) 6AN O-ring outlet, and (1) 6AN O-ring return.

• Boost Referenced: Offers a 1:1 boost reference capability for forced induction applications.

• Manifold Reference & Gauge Port: Comes with a manifold reference fitting and an 1/8" NPT gauge port.

• Includes Dual Springs: Ships with a 4-15 PSI spring pre-installed for carbs, plus an EFI spring for up to 65 PSI.

Whether you're feeding a mild carb or a high-pressure EFI system, the Holley 12-880 regulator gives you precise control, durability, and race-ready reliability.