Power Valve ID

[Jeff Joyce]

The power valve in this Holley 2300 rebuild kit is different than the original. The original (on right in pic) doesn't have any identifying numbers on it. The power valve provided in this rebuild kit (on left of attached pic) has an "A3" stamped and the number "17" on the back side and there's a tiny "4" cast into the front side. I can't find anything online with those numbers.

I think the new power valve is a 2-stage. I've read a few guys saying 2-stage power valves were preferred. I found a few pics of 2-stage power valves online and it appears to be similar.

My question, can anyone ID this other power valve? It fits into the carb body upon mock up, so I could use it.

FYI, I'm rebuilding this carb for a 304 on a 2wd 1010 pickup. It ran great but leaked fuel onto the intake and also "poured" fuel into the venturis/intake after shutdown. Couldn't tell exactly where it was leaking from or why it was leaking fuel from the bowl to the venturis after shutdown. I thought a rebuild would solve the issue. I'm afriad the fuel leaking into the venturis could be an issue with the power valve, so I don't want to reuse the old one and want to use this new one. Thoughts?

[WRENCH MAN]

the one on the left has an anti back fire valve incorporated into it, IH used these OEM, the one on the right doesn't, it's also the more common one, the "17" indicates the vacuum at which it opens and closes, 17 seem rather high to me? as would the 3 or 4 would seem WAY to low??

If your carb is dumping fuel down the venturis it most likely has some CRUD in the needle and seat.

[Jeff Joyce]

Originally Posted by WRENCH MAN

the one on the left has an anti back fire valve incorporated into it, IH used these OEM, the one on the left doesn't, it's also the more common one, the "17" indicates the vacuum at which it opens and closes, 17 seem rather high to me? as would the 3 or 4 would seem WAY to low??

If your carb is dumping fuel down the venturis it most likely has some CRUD in the needle and seat.

Thanks for the reponse. So, which one has the anti-backfire? You said left twice.

The fuel "dumping" is only after I've shutdown the engine (mech fuel pump). Given that information, do you still think it's an issue with the needle and seat? I thought that when the engine is off it wouldn't matter if the needle valve is open, the pump's not pumpin'.

I pulled and disassembled the carb tonight. The needle moves freely. Not saying you're wrong, I just want to understand your logic.

-Jeff

[71 Scout 2]

Just personal opinion, but for major Holley carb parts (like power valves) I now only use actual Holley parts. I've had too many of the generic kits where the power valve was way off. The last generic two stage valve I tested was suppose to partially open at 14" and fully open at 4". It tested at 5" and 2" respectfully.

[WRENCH MAN]

Originally Posted by Jeff Joyce

Thanks for the reponse. So, which one has the anti-backfire? You said left twice.

The one on the left.

[70binderPA]

the # on powervalves is twice that of the vacuum they open at

[Jeff Joyce]

Originally Posted by 70binderPA

the # on powervalves is twice that of the vacuum they open at

So I have a two stage that operates at ~8-9" on the first stage and 1.5" on the second stage?

Are those values too low? It appears to be the lowests settings for any I can find for sale online. I also read up on power valve tuning and it seems that stock setups (which typically have higher vacuum, pushing 18") should have PVs with higher setpoints, say 10-12. I assume the worry is a lean condition under load, which could cause pinging and potential engine damage over time.

I don't think I could make the manifold vacuum dip to 1.5".

[71 Scout 2]

Originally Posted by 70binderPA

the # on powervalves is twice that of the vacuum they open at

If that's the case every single Holley power valve I've tested was bad.

I've tested a couple dozen valves over the years and all the Holley power valves closed with the amount of vacuum that was equal to the number(s) stamped on them.

[SCscoutguy]

Originally Posted by 71 Scout 2

If that's the case every single Holley power valve I've tested was bad.

I've tested a couple dozen valves over the years and all the Holley power valves closed with the amount of vacuum that was equal to the number(s) stamped on them.

This is what I have always found as well. The number stamped on it was what it actually was. I think the problem comes when you use other than a actual Holley made power valve then they start labeling them differently.

[Thomas]

---The power valve on the left is an AED power valve that is adjustable. Sorry to say it, but you have wasted your money. I suggest you throw everything, less the red, reusable bowl and metering plate gaskets in the trash and save yourself the heart-ache. If you purchased a full 2300 rebuild kit that has the new fasteners, DO NOT attempt to use the fasteners as they will strip the threads out of your main body and you will have to spend more $$$ to purchase HOLLEY'S inserts to repair the threads. The fasteners have a slightly smaller ID shank and they will* strip out the threads.

---Words that will save you trouble... Purchase ONLY Genuine* Holley parts and gaskets for your Holley carburetor.

---AFAIK, there is no such thing as an anti-blow out power valve... there is only an anti blow-out check ball that you assemble into the base plate of the carburetor after drilling it out with the drill bit that comes in a kit with a check ball, spring and retainer.