Holley 32 GPH Mighty Mite Electric Fuel Pump 12-427 — 4–7 PSI, 12V Self-Priming

The Holley 12-427 Mighty Mite is a 12-volt electric in-line fuel pump delivering 32 gallons per hour at a regulated 4–7 PSI for street and race applications up to about 400 HP naturally aspirated engines.

Compact and purpose-built, the Holley 12-427 combines a solid-state electric motor with a self-priming, regulating design. It’s built to replace or upgrade factory pumps on classic cars, project builds and many aftermarket fuel systems. The unit is compatible with a wide variety of fuels and additives, features a simple two-wire hookup and is rated for reliable operation in common automotive environments.

How much flow and pressure does the Holley 12-427 provide?

This pump is specified to deliver approximately 32 gallons per hour while maintaining an operating pressure between 4 and 7 PSI. That flow and pressure combination is optimized for many carbureted or low-pressure fuel injection setups on naturally aspirated engines up to roughly 400 HP.

• Rated flow: 32 GPH (gallons per hour)
• Operating pressure range: 4–7 PSI
• Suitable for up to ~400 HP naturally aspirated engines
• Self-regulating operation for stable pressure under load

Which fuels and environments is this pump compatible with?

The 12-427 is designed to handle a broad array of fuel types used in performance and street applications. Its materials and construction accept gasoline, diesel blends, ethanol blends (including E85) and common fuel additives. Note that it is not certified or intended for aviation use.

• Compatible with gas, diesel, blended alcohol, ethanol and E85
• Resists common additives used in performance tuning
• Not intended or approved for aircraft applications
• Designed for automotive and motorsport operating conditions

How easy is installation and what are the key electrical specs?

Installation is straightforward: the pump runs on 12 volts and requires a simple two-wire connection. Its solid-state design reduces moving electrical parts for longer service life, and it is self-priming with a 12-inch dry lift capability to simplify mounting options.

• 12-volt operation with simple two-wire hookup
• Solid-state motor design for improved durability
• Self-priming and capable of 12" dry lift
• Compact form factor for in-line or retrofit mounting

What reliability and performance characteristics should I expect?

Holley designed the Mighty Mite to offer consistent delivery under moderate performance loads while minimizing electrical wear. The pump’s engineering aims to provide dependable operation in street and performance settings when used within its rated flow and pressure limits.

• Solid-state construction for extended operational life
• Regulating action helps maintain steady fuel pressure
• Suitable for continuous use within specified ratings
• Simple maintenance and serviceability when required

Who is this for: The Holley 12-427 is intended for enthusiasts and mechanics upgrading fuel delivery on classic cars, street rods, performance street machines and many retrofit projects that require a dependable 12V in-line pump. It fits applications that need moderate flow at low pressure — particularly carbureted engines or low-pressure injection systems — and where compatibility with ethanol and other blended fuels is important. If you need a higher-pressure or higher-flow solution for forced induction or high-horsepower builds, evaluate pumps rated beyond this model’s 32 GPH/4–7 PSI range.