[RickD]

I just installed a fuel pressure gauge and fired up the ol' 355 after working on the car since last november ( yeah! ). The gauge shows 8# pressure. I have been chasing a rich condition and am wondering if this is the culprit. I have a mechanical pump of unknown make, holley 700 dbl pumper. Is this pressure high enough to force gas through the carb? Holley tech line says my jetting should be about right.

[davidpozzi]

Have you set the floats using the side plugs?
At what speed is it rich?

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The older I get, the faster I was!

[This message has been edited by davidpozzi (edited 06-07-2000).]

[RickD]

Yes, I did set the floats. I pulled the plugs and they were borderline dark chocolate/black. I have new wires, plugs, cap, rotor, Accel 300+ ignition. How do I tell at what speed it runs rich? Is 8# enough to do something about?

[bruce ulrich]

have you thought about the power valve it is rich at idle low end most holley come with a 65 power valve this means it opens at 6.5" of vacuum put a vacuum gauge on the manifold meaning below the throttle blades of carb and lets say the engine idles with 10" put a 50 power valve in carb if you think that you have to much fuel pressure holley make a needle and seat that will hold higher pressure also holley fuel regulator that go in line are not that much money I have had this problem with race cars in past
and when I looked down the air horn I could see to much gas in venturas It semms like the number of 7 lbs comes to mind to me though on fuel possiblibly getting past needle hope this helps
bruce ulrich
67 bb conv

[RickD]

My vacuum is 14" so I think the 65 is OK. I ordered the Holley regulator from Summit. Several articles I've read say about 5 pounds pressure. Holley's website says their carbs will handle up to about 8# so I think I'm borderline. I'm going to adjust it to 6 and see how it is. When I took the primary bowl and assembly off to check the jets and power valve, I found the power valve was loose. That may be the culprit.

[RockyMtnRacer]

I've seen the fuel pressure question come up several times and I've posted it myself. For some reason the question seems to go unanswered.

My Edelbrock carb is spec'ed at 5 psi max. My guage tells me I have 9psi (and sometimes only 5 for no apparent reason) at idle. I continue to wonder if this is causing any problems but no one on the site (or anyone else I've asked) has had any answers??

I just e-mailed the Edelbrock tech line - I'll post their response.

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Scott
'69 400SB, Richmond 5-speed; '99 HD Road King Classic
www.geocities.com/sdenning1

[RickD]

Well, I would think that if Edelbrock says 5#, then 9# will cause you a problem sooner or later. However, unless someone chimes in with experience ( please ), I guess an over-rich condition would develop as additional fuel is forced through the carb. Sooo, I'm going on the assumption that the manufacturers have reason on their side for making recommendations. Can't hurt.

[Lonnie67]

All of the small 1" fuel pressure guages I've seen are inaccurate. Something to check if you have one. I think 8 is a bit to high for a holley. I run 7.

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67 Camaro 410sb 11.63 @117.6
67 Camaro 388 ET-???
website

[RockyMtnRacer]

The edelbrock guys said if the carb wasn't leaking gas to leave the pressure alone. Otherwise, regulate the pressure down to 5-1/2 psi. They didn't address any tuning or driveability issues at all.


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Scott
'69 400SB, Richmond 5-speed; '99 HD Road King Classic
www.geocities.com/sdenning1