Power Valve Id Please
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Senior User
Joined: Sep 2004
Posts: 279
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From: Appleton, Wisconsin
Power Valve Id Please
In my gallery I posted a drawing that shows the numbers on the bottom of my power Valve in my holley 94 carb for a 239 flathead V8.
I want to know if these numbers ID the vacuum, and if these numbers are correct for the carb type.
thanks!
I want to know if these numbers ID the vacuum, and if these numbers are correct for the carb type.
thanks!
Fleet Owner
Joined: Jul 2004
Posts: 27,294
Likes: 1,055
From: NM
Yep, they save a few yuan by not stamping them, probably because they can't guarantee their performance, anyway. I had my gas mileage drop 10% after a carb rebuild on a 302, and it turned out to be the new power valve that came in a kit. If you go direct to an idividual Holley part #(like at a speed shop) they seem pretty consistent, and it's worth playing around with vac settings (# on the valve) to see what one works best for your overall engine setup and location. Unfortunately it's not a 5-minute job to swap them out.
As I recall, you said in a previous post you were at 1700'? I would think stock settings for jets and power valve would be the place to start. MT and I are a almost a mile above you, adjustments are needed up here.
As I recall, you said in a previous post you were at 1700'? I would think stock settings for jets and power valve would be the place to start. MT and I are a almost a mile above you, adjustments are needed up here.
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Senior User
Joined: Sep 2004
Posts: 279
Likes: 0
From: Appleton, Wisconsin
I just picked up 51 Jets from Holley. And I ordered a idle mixture adjustment screw. I HAD ONLY ONE EXPOSED ON THE CARB. I"VE ALWAYS THOUGHT IT WS SUPPOSED TO HAVE ONE! when it took the carb off I noticed a broke off screw. I bet to needles will help the mileage a bit
!
Do you know what the Power Valve vacuuum setting should be stock for this?
Before I put the carb all back together and fire it up I'd like to try a new power valve thats actually made by Holley
!
Do you know what the Power Valve vacuuum setting should be stock for this?
Before I put the carb all back together and fire it up I'd like to try a new power valve thats actually made by Holley
Posting Guru
Joined: Jan 2002
Posts: 1,002
Likes: 2
From: Midland, Texas
You need the 7.5 to keep it stock with your #51 jets. New Holley PVs have larger diameter brass gizmos on the top of the valve where the spring is. This necessitates a bit of grinding on the bowl... a small verticle groove cut with a Dremel and 1/4" bit should do it. There is a difference in the gasket diameters old to new. This can cause poor seals when using a new style PV and the earlier model. I would seek out the earlier style PV from a vendor.
poorly power valved, himmelberg
poorly power valved, himmelberg
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