Holley 4150 4160 Power Circuit

Power Valve Restrictions

Holley 4 Barrel Power Valve
Restrictions or PVCRs determine the amount of fuel that the power circuit can flow into main well.
Holley 4150 Power Circuit
Holley 2 Stage Power Valve

Holley carburetors for the street -especially those manufactured for 1973 and later engines with EGR systems -use two-stage power valves (see illustration). Staged power
valves open partially at one vacuum level, then open fully when manifold vacuum falls to a lower level. The first stage in these valves opens a metering orifice smaller than the PVCR. Two stage power valves are used on some replacement carburetors to help certain engines pass emission tests. They’re also available as replacement parts for vehicles with a relatively low power-to-weight ratio, such as recreational vehicles and station wagons.

Holley 4150 Power Valves
Updated on 03/10/2021

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