Autolite 4100 Power Valve 1 Stage 70-100B

Autolite Holley Power Valve 1 Stage 70-100B

17 Review(s)

Your Price: $12.95

Part Number: 70-100B

Availability: In Stock

Motorcraft Power Valve *

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Autolite 4100, 4 barrel power valve, Motorcraft 2100. Also fits many of the Holley 2-barrels & 4 barrel carburetors. Please select your power valve from the drop down list. 7.5 & 8.5 inch HG are the average size that are installed in the stock engine.

These are Holley style power valves with a lip around the outer edge for the gasket to sit into. Some of the Holley 94 carbs use this style and some use a power valve with a flat mating surface like the 70-485.

Power valves used to blow out anytime an engine back fired, but today's power valves are designed to last.

Under normal circumstances the power valve size in our carburetor kits are the correct size.

Under not so normal circumstances such as a built up engine, multiple carburetors the vacuum will be reduced and will require a power valve that opens up quicker.

How to read the HG on our power valves. Look at the face of the power valve (the shiny surface). Turn the valve so the number reads correctly and is on the right side. Example 8. Read the number at the bottom. Example 5. You have a power valve with 8.5HG.

The power valve stays closed until it reaches it's rated HG. In the example above the power valve won't open until the vacuum drops to 8.5HG.

High performance and engines with multiple carburetors will have a lower vacuum reading thus requiring a lower power valve.

Determine your power valve size by connecting a vacuum gauge to the manifold and read the HG under power (hold the break on and power up) and divide by 2 and round to the next .5 For example a reading of 15 HG would require a power valve size of 7.5 HG.

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5.0

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good quality part

Purchased this for my bronco 2 with a 2150 ford carburetor. My power valve was blown and flooding my bronco intake with gas at idle. I did not know how to identify my power or that there were different ones that reacted to different vaccum levels. Mikes carbs has a application chart and power valve identification chart showing me where to look on my old one in order to identify its vaccum rating. I love sites like that that are dedicated to getting a customer the correct part. I didn't have to take a chance on amazon. My local parts house carquest and Napa neither one had a clue what power valve was correct for my carbuerator, they told me to call the dealership lol. That was another joke no one could even identify the power valve they looked at it and matched it to one that looked like it. My bronco flooded when I gave it fuel in third gear until I got it up to about 65 in 5th gear. Morale of my story, ,, when your dealing with sensitive vehicle parts that work in conjunction with other parts get your parts from someone who specializes in those parts. I will always buy from mikes carbs. Oh. The power valve I got from Napa cost me 23 buck and they wouldn't take it back or refund my money. The one I got from mikes carbs worked perfect due to the fitting chart. Thanks mikes carbs. I love dealing with a company that actually turns my problem into there on and finds a solution for me.

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Reviewed by: andy from idaho on 11/4/2015

Excellent replacement

This power valve is an excellent replacement for the power valve that was leaking in my Motorcraft 2150 carburetor. The gasket that came with it was much thicker than the one I replaced which I also liked. Good value.

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Reviewed by: Patrick Lynch from Paris, KY on 3/24/2020

60 t-bird owner

reasonable price and fast shipping,i also used tech article on setting the accelerator pump on 4100

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Reviewed by: kevin from barre,ma on 9/30/2014

Happy Customer

I replaced the 7 HG power valves with 2.5 HG power valves in my 1936 P-U that has dual carbs and in made a big improvement in the over all performace.

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Reviewed by: Joe Coleman from White City, Or. on 7/9/2014

Autolite 4100 Power valve

I'm very happy with the parts I ordered. They fit well and were at a good price.

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Reviewed by: PAUL from Torrance on 2/19/2023

MECHANIC

oooh AHHH Works Perfect!

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Reviewed by: steve vlachos from santa ana on 11/5/2021

Excellent product. Matched the motorcraft carb. Worked well and easy to install

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Reviewed by: John from MS on 10/25/2019

Mechanic

Great will use your company again

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Reviewed by: Brad Phillips’s from Hernando Mississippi on 6/23/2019

Owner Ricky's Garage

Great service fast and helpful. Product as described . No surprises .

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Reviewed by: Ricky moye from Wv on 5/22/2018

Rocket Bird!

The 9.5 power valve (vs 7.5 standard) was used in combination with #57 jets (vs #54 standard) to address an acceleration stumble in my 61 Thunderbird with slightly modified 390 engine and 4100 carburetor. Excellent parts. Thanks VERY much.

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Reviewed by: Bill from Chesapeake, VA on 6/18/2017

Autolite Holley Power Valve 1 Stage 70-100B

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