I am pretty sure that I blew my power valve during start up on my new motor, had a little fire action. I know that there have been posted about this and I tried to search for them but could not find them. Can I get some suggestions on where to start. At one point I believe that I was told to get a 8.5 and 10 but don't know? Also any other tuning suggesting would be great. I plan on placing a order with summit for the Chrysler linkage adaptor ( 20-7) for the quick change secondary vacuum with springs

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225+0.080 at 10:1
268cam
holley 390
clifford headers
8 3/4 355's lsd
kh brakes
electronic ing

You want to have a power valve that opens when the enrichment circuit is needed.

What is your cruise vacuum? Normal road cars will have between 15 and 19 inches of mercury at cruise. The 10.5 was good for my Plymouth running a mild cam.

You want to have at least 2" HG lower than manifold vacuum at cruise. And certainly lower than idle vacuum in gear. If your cam choice has your vacuum at 8" HG, for instance, you want a 6. The enrichment circuit should not be flowing fuel during cruise or idle times.

You don't want a dual stage power valve. It won't flow enough fuel.

For most slant six street builds, a high flow 10.5 PV is the right choice.

There is a kit available for early Holley four barrels to protect the power valve from blowing out. If yours doesn't have the anti-blow out valve, you will want to install the kit.

CJ

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Part of Tyrde-Browne Racing

Thank you I have know Idea on the vacuum on the car I had the motor built about 3 years ago and yesterday was the first time that I fired it up. I have to tighten up a few odds and end be for I can road test it.

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225+0.080 at 10:1
268cam
holley 390
clifford headers
8 3/4 355's lsd
kh brakes
electronic ing

Only if drag racing and needing all out fuel flow, it actually works great if you have the engine dialed in and need better mileage on the street with a heavy car and/or using a moderate performance cam (say nothing heavier than the Erson 280/270....), even in a 10:1 engine with the 280/270, the 390 holley and the 6.5/12.5 unit will give good mileage on the street...but I'd switch at the track to a 10.5PV...
Over the counter Spectre make a $6.95 kit that will do the job and you will just need a drill, pliers, and a throttle plate gasket... best bang for the buck.

-D.Idiot

[url=http://www.holley.com/0-8007.asp]Holley site[/url] has helpful technical videos covering your questions. Click on “Technicalâ€￾ Tab for a drop down menu. There is a video covering power valve selection, and blow out modification to older carbs.

An easy test for blown power valve diaphragm is to remove it from carb, and try to suck air through side of valve without spring. If it passes air it is no good.

You need to get a vacuum gage, and a pick up a long enough length of vacuum hose to be able to have gage on top of dash board while attached to carburetor. Once you can view vacuum readings while under way, you can better select a power valve, and begin to understand when it activates while driving.

The next step in Holley tuning is to install an o2 sensor, and A/F gage to fully understand and tune that 8007. This [url=http://www.bob2000.com/carb.htm]site[/url] will explain this tool, and purchase a few books on Holley tuning to maintain sanity.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC