A mechanical fuel pressure regulator for automotive use, designed to deliver steady control between 4.5 and 9 psi. Useful for restorations and performance tuning, Holley Fuel Pressure Regulator 12-803 brings more predictable carburettor behaviour and simpler jetting. Will it suit a vehicle-specific installation and long-term maintenance plans?
⚡ At a Glance
- • Pressure Control: Adjustable regulation from 4.5 to 9 psi for stable fuel delivery
- • Best for: Carburettor-equipped vehicles, restorations and performance tuning where mechanical regulation is preferred
- • Not ideal for: Applications that require pressure ranges outside 4.5–9 psi
Adjustable range covers common carburettor requirements. Simple mechanical design uses standard fittings for straightforward installation.
Precise pressure tuning – with adjustable 4.5–9 psi range
Adjustment allows pressure to be set between 4.5 and 9 psi, matching many carburettor specifications without electronic control. The mechanical range gives clear, repeatable settings for jetting and tuning.
Fine-tune fuel pressure for cleaner idling and crisper throttle response, making jetting adjustments simpler and more predictable.
Stable fuel delivery – with .220 inch (7/32 inch) restriction
A .220 inch restriction creates a calibrated orifice that moderates peak flow and helps maintain steady pressure under changing engine demand. That measured limitation reduces sudden pressure spikes.
Reduced pressure surges mean fewer rich conditions during acceleration and more consistent running across throttle positions.
Straightforward installation – with 3/8 inch NPT ports and mounting bracket included
3/8 inch NPT inlet and two outlet ports match common fuel line fittings and the supplied mounting bracket supports secure attachment to the chassis. Standard plumbing reduces the need for special adapters.
Faster fitment for vehicle-specific restorations and simpler plumbing during upgrades or replacements.
✨ The 4 Key Reasons for Holley Fuel Pressure Regulator 12-803
.220 inch restriction — Controls peak flow for steadier carburettor fuel delivery during acceleration
3/8 inch NPT ports — Simplifies plumbing with common fittings and secure connections
Mounting bracket included — Allows secure attachment without sourcing extra hardware for rapid installation
Durable, long-lasting build — Reduces need for frequent replacement in high-vibration environments
📋 Technical Details at a Glance
- Category: Automotive - Fuel Pressure Regulator
- Model: 12-803
- Brand: Holley
- Pressure Range: 4.5 to 9 psi
- Restriction: .220 inch (7/32 inch)
❓ Frequently Asked Questions
Q: What pressure range can be set?
A: The regulator is adjustable between 4.5 and 9 psi, covering common carburettor requirements.
Q: What ports and thread sizes are used?
A: Ports are 3/8 inch NPT, configured as one inlet and two outlets for standard fuel plumbing.
Q: Is a mounting bracket included?
A: Yes, a mounting bracket is included to help secure the regulator during installation.
🏆 Our Verdict
The Holley Fuel Pressure Regulator 12-803 suits mechanics, restorers and enthusiasts working with carburettor-equipped vehicles who want simple, mechanical regulation. Adjustable 4.5–9 psi control, a .220 inch restriction and standard 3/8 inch NPT fittings make it a practical choice for stable tuning and straightforward installation. Although retail cost varies, the robust, long-lasting design and standard fittings typically deliver good long-term value for restoration and tuning projects.
