power valve question Holley 94

[Gary in Mozarks]

I have two power valves, One is marked 14 and the other is marked 10 on the edge. what do those numbers mean? Which one should I use for a single carb stock holley on a 59 engine?

[JWL]

I am not familiar with either of those designations. If they both came from standard rebuild kits, either should work ok if they seal to the body correctly.

[ken ct]

Neither one is correct Never heard of a #14 and the #10 is also opens too quick. Use a 5.5 # in that 94. I have them. also use .049 main jets. ken ct. I dont know where you ever got a kit with those 3's in it must be a China job. [you get what you pay for] ken ct.

[Gary in Mozarks]

Those power valves were removed (used) from the two carbs I have here. I was mostly trying to understand the numbering system. The numbers are very small on the edge of the top surface of the power valve. Is that where they are usually marked?

[JWL]

The identification marking locations can vary by manufacturer. The numbers on your valves are not consistent with vacuum rating numbers and must be a code of some sort. The only way to actually "know" the rating is to pull a vacuum in a gaged chamber. I can do that for you but it ain't worth the shipping costs. The valves, if not ruptured, are likely to be just fine as to vacuum opening point.

[Dee]

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The power valve and it's seal are important and whether you chose to use the standard 7.5 ( in/Hg) or the lower value 5.5 it's also important to have a good vacuum seal in the base chamber below the valve. More than likely the carburetor bodies are warped and the bottom surface needs to be trued , flattened. The mating surface on the throttle base should also be checked. A good seal around the cavity for the power valve will assure that the value numbers of the power valve actually mean something.

[Gary in Mozarks]

Here is a picture of the 14

[BUBBAS IGNITION]

For some reason there was a period of time or a manufacture that used a double number on the valves ( got that in a holley book here somewhere) .

I think you will find that the 14 is a 7 inch valve and the 10 is a 5 inch valve......

[Gary in Mozarks]

Bubba, That makes sense, Thank you, Seems like I read somewhere you could check if a power valve is blown by suckin on it somehow, Is that true?

[ken ct]

Yea that will check if the diafram is leaking but will not tell you the # of it.The higher the # the faster it will open and dump massive fuel into the system. {not good}.Best all round # is a 5.5. Most China kits have a 7.5 [too high]. Most have 's on them if you know how to read them. High #'s have a fairly strong spring on them.Low #'s have a lighter one on them.Dual setups can use 4.5 or even 2 3.5 ones. Get your self a 5.5 and you will be a happy camper and .049 M jets. ken ct.

[coolcoupe]

Hi Ken, how do I get the 5.5 pv and 49 jets from you? If you send me your address I can send you a cheque or money order. Thanks Coolcoupe

[ken ct]

Coolcoupe, check your PM's. ken ct.

[hellmet]

A old timer said he never uses power valve's he just plugs the hole any theory on this? This has guy used to race a lot and build nice race motors.

[bobscogin]

Originally Posted by hellmet

A old timer said he never uses power valve's he just plugs the hole any theory on this? This has guy used to race a lot and build nice race motors.

Race engines and street engines are different animals. You could probably block the power valve on a race engine since it's tuned to run in a very narrow RPM range. Jet it for maximum power at the top of the power band and you're good to go. Don't expect to get a proper fuel curve at any other RPM, however, and that would make for a street engine that didn't run correctly.

Bob