Originally posted by DennyW
600 Holley :
Power Valves and Carburetors for Superchargers
These carburetors that are intended for use with superchargers, and have a unique capability that allows their power valves to reference the intake manifold vacuum below the supercharger. This allows the power valve to operate as it should, based off intake manifold vacuum. A power valve provides further enrichment to the main metering system under load (low vacuum) conditions. Without this external referencing, the power valve would be "reading" the supercharger boost pressure, which has no bearing on the engine load.
So, is these carbs for a charger for sure?
never knew i had a power valve problem, but i almose took the blower off on accont of the floats. the people at blower serv. told me there was no way a 471 blower would sink a float so i keeped looking for something else, but wouldnt you know it i had one that would.