Holley Single-Stage Power Valve Available Sizes 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5

• Single-stage power valve for Holley performance carburettors using replaceable screw-in power valves
• Common applications include Holley 2300 2-barrel, 4150 4-barrel, 4160 4-barrel and many 4500 Dominator-style carburettors
• Available in multiple vacuum ratings from 2.5 to 10.5
• Restores correct power enrichment under load and wide-open throttle

Holley single-stage power valves are a critical component of the power enrichment circuit in Holley performance carburettors. They operate using engine vacuum to control when additional fuel is supplied to the main system. Under light throttle and cruise conditions, the valve remains closed. As engine load increases and vacuum drops, the valve opens to deliver extra fuel, helping prevent lean conditions, hesitation and bogging while supporting smooth and responsive power delivery.

These single-stage power valves suit many popular Holley carburettor applications, including 2300 2-barrel models, 4150 and 4160 4-barrel square-bore carburettors, Double Pumper-style carburettors, vacuum secondary models, Street/Strip and HP-style carburettors, and many 4500 Dominator-style carburettors that use a standard replaceable Holley power valve.

Fitment should always be confirmed against your carburettor model or Holley list number, as some carburettors may use different power valve configurations, power valve blanks, two-stage valves or application-specific metering blocks.

These single-stage power valves are available in a wide range of vacuum ratings, allowing precise tuning to suit your engine combination and driving style. Each valve includes a gasket and is designed to provide reliable operation across street, strip and performance applications.

Common Applications

• Holley 2300 2-barrel carburettors
• Holley 4150 4-barrel carburettors
• Holley 4160 4-barrel carburettors
• Many Holley 4500 Dominator-style carburettors
• Many Holley Double Pumper, vacuum secondary, Street/Strip and HP-style carburettors using standard replaceable power valves

Power Valve Selection Guide

One of the simplest ways to select the correct power valve is to measure manifold vacuum at idle with the transmission in gear for automatic vehicles. The recommended power valve rating is approximately half of this vacuum reading.

Example: If your engine produces 20 inches of manifold vacuum at idle, the appropriate power valve would be a 10.5.

Specifications

• Product: Holley Single-Stage Power Valve
• Design: Single-stage
• Vacuum Ratings Available: 2.5, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5, 9.5, 10.5
• Function: Power enrichment under load and full throttle
• Compatibility: Holley performance carburettors using standard replaceable single-stage power valves
• Common Carburettor Families: Holley 2300, 4150, 4160 and many 4500 Dominator-style carburettors
• Gasket: Included

Inclusions

• 1 x Holley single-stage power valve, selected vacuum rating
• Power valve gasket

Why Choose Gator Carburettor Parts?

• Wide range of Holley tuning components available in stock
• Accurate product information to help select the correct power valve
• Australian supplier specialising in carburettor performance and tuning parts