Holley, Ford Autolite Power Valve / Enrichment Assembly
Ford Motorcraft Autolight 4100 carburetors
Ford Motorcraft Autolight 2100, 2150 carburetors
Number of Stages: 1 Stage
Vacuum rating: 2.5" HG
Over All Length: 1.1"
Power valve head diameter: 1"
Power valves supply additional fuel to the main system during heavy load or full power situations. Power valves are rated to indicate the vacuum opening point. For example, a power valve rated at 5.5” will open when the engine vacuum drops to 5.5" or below.
Generally, the power valve selected should be 1/2 the idle intake manifold vacuum reading. EXAMPLE: 15” Hg vacuum reading divided by 2 = 7.5 power valve. Most Stock engine combinations require either 7.5" or 8.5" power valve.