66 396 fuel pressure - Chevelle Tech
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post #1 of 7 (permalink) Old Jul 9th, 20, 6:07 PM Thread Starter
Ron
 
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66 396 fuel pressure

I have a 396 325 hp EDH Holley code. Stock rebuilt carb that is fed with stock style mechanical fuel pump.
The carb has had issues of seeping fuel at base gasket after shut down and sitting for a few days.
It has 110 needle and seats, has been rechecked on other engine and no issue. My fuel pump is Spectra that I have measured pressure at 8psi at engine cranking speed.
So is 8psi an issue for Holley to hold that pressure from go past needle and seat?
Is there any way to bring pressure down or just keep trying different pumps?
Specs on this pump are 5.5 to 6 psi and this pump has the correct connections on outlet for OEM style line.
Other brand pumps have flare female outlet, this one is 1/4 pipe for correct elbow.

Last edited by RSRon; Jul 9th, 20 at 6:17 PM. Reason: picture
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post #2 of 7 (permalink) Old Jul 10th, 20, 12:46 AM
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Re: 66 396 fuel pressure

8-8.5 psi is what the Holleys I have had could hold.
But if you 8 psi cranking you probably have more with engine running.

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post #3 of 7 (permalink) Old Jul 10th, 20, 10:22 AM
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Re: 66 396 fuel pressure

Quote:
Originally Posted by RSRon View Post
"has been rechecked on other engine and no issue."
You put this little statement in your post, I cant help but wander if your manifold may be warped slightly. Are you using a factory steel manifold or an aftermarket aluminum manifold? Suggest trying to double up on the base gasket and see if it seals. Also, torque the carb nuts to spec, and use flat washers under the nuts.

But Yes, 8 psi is a bit high for a factory carb. It should be in the 5.5-7 psi range.

Chris
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post #4 of 7 (permalink) Old Jul 10th, 20, 10:20 PM Thread Starter
Ron
 
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Re: 66 396 fuel pressure

Leaks at base plate gasket, not mounting gasket. Factory Holley intake, surface machined when engine rebuilt
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post #5 of 7 (permalink) Old Jul 11th, 20, 12:18 AM
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Re: 66 396 fuel pressure

Quote:
Originally Posted by RSRon View Post
Leaks at base plate gasket, not mounting gasket. Factory Holley intake, surface machined when engine rebuilt
If I'm understanding you correctly ? your carb is leaking where the throttle body and the carbs main body bolt together ?
I forget what they're really called but have you tried the blue gaskets that solve that problem ?

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post #6 of 7 (permalink) Old Jul 13th, 20, 8:04 PM Thread Starter
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Re: 66 396 fuel pressure

The gasket from throttle bores, to base plate
No I have not tried any blue gasket, I'm thinking the seepage I see is from other issue than just the gasket being bad.
Fuel pressure is higher than I would like, but no way to get it down except keep buying mechanical pumps.
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post #7 of 7 (permalink) Old Jul 13th, 20, 10:56 PM
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Re: 66 396 fuel pressure

Have you checked your float level?

You're just jealous because you can't hear the voices!

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