I was at 5.5psi, now I'm down to 4.5psi. I figure I am still OK, but I'm also still running rich (though not as much). I have heard of people running as low as 3.5psi... what is the lowest one should turn the psi down to?

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

I've run as low as 2 or 3 with no problems. If you run out of gas up top..you will know it.

 

It'll be a lot more sensitive to low volume than low pressure.

 

The good "great" thing about holley carbs are the float levels You can set them for fairly high volume and low with no problems. Id like to see an edelcrock be as adjustable.
As far a low pressure "volume" I had the regulator down to 3 PSI but I had the floats almost all the way up.
SSC

 

pressure isn't the same as 'volume' If you can maintain 2psi all the time--at any given volume you never run out of gas. A carb needs volume.

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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, currant red metallic paint. Lots of other stuff...
82camaro

 

So I have a Carter high volume mech pump, so I should be OK as far as that goes. I may need to go back up one jets size I guess... I'm at 68 now. I'll see how it looks once I drop the psi a little more. Thanks guys!

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

If you're running rich, you'll want to go DOWN a few jet sizes to maybe a 66.

3PSI is the lower limit on pressure. Any less and there simply isn't enough pressure to push enough gas through the needle valve to keep the engine fed at high RPMs.