Holley Power Valve 5.5
Single-stage vacuum-operated carburetor enrichment valve opening when manifold vacuum falls to 5.5 inHg.
Holley 5.5 is a single-stage vacuum-operated carburetor power valve. It opens an additional fuel-enrichment passage when intake-manifold vacuum falls to 5.5 inHg or below, typically during high engine load and large throttle opening.
Application / fitment
The part is intended for carburetors using the common screw-in Holley-style power valve found in many 2300, 4150 and 4160-family applications. Compare the thread, diameter, gasket and old-valve construction before ordering because not every Holley carburetor or compatible aftermarket unit uses the same design.
- opening rating: 5.5 inHg
- typical valve stamp: 55
- type: single-stage enrichment valve
- function: additional fuel enrichment under load
Holley recommends an initial rating approximately one-half of the fully warmed engine vacuum at idle; this valve is a starting point for an engine showing approximately 11 inHg. Measure an automatic-transmission vehicle while idling in gear and a manual-transmission vehicle in neutral. Final selection requires checking air-fuel ratio and engine response under load.
Technical information
- product type: vacuum-operated carburetor power valve
- stages: 1
- opening vacuum: 5.5 inHg
- sales unit: 1 valve
- installation: use the correct undamaged gasket
- note: the rating is not fuel pressure or jet size