Holley float levels?

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Holley float levels?

Postby sugaryuk » Sat Apr 04, 2015 9:05 pm

My carbs were leaking a bit so I'm in the process of freshening up the gaskets. My current set up is dual holley 750's (#4779-9 --blower carbs?) on a 383 stroker with a 671 blower. Anyone know what the float levels should be for a holley 4779-9 carb? Closest I can find is for a 4779-2AAA--it's 13/16" for primary and 1/2" for secondary. But from what it looks like the previous setting was closer to 11/16" for the primary (haven't done the secondary yet). Would a custom tune have this much of a difference in levels? Thanks for any input!
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Re: Holley float levels?

Postby spencerforhire » Sat Apr 04, 2015 9:45 pm

Whatever it is, the base setting will need to be tweaked with the motor running anyway. That's why there's a sight plug in the side of the fuel bowl. You can adjust so the fuel just barely dribbles out, or install clear sight plugs.
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Re: Holley float levels?

Postby sugaryuk » Sat Apr 04, 2015 10:01 pm

Which base setting would you recommend? Is there a standard setting for my application? I haven't worked with carbs for years (dam computer based cars :x !) so any help is appreciated! I was having a problem with the car stuttering while under load so it certainly needs a re-tune. Is it better to have the floats set high or low prior to fine tuning?
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Re: Holley float levels?

Postby chevyart » Sat Apr 04, 2015 11:45 pm

take float bowls off, and turn upside down and the bottom of the float bowl should be level(parallel with bottom of float bowl. if it isnt, adjust it with the adjust nut on needle and seat. this should get you very close to being right on, and then check with motor running and gas should just be trickling out bottom of sight plug hole. do this with car on level ground.. i have even done this with the motor off, by just rocking car slightly and the gas will overflow slightly out bottom of sight plug hole. if it does this, you are close to being right on. art
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Re: Holley float levels?

Postby sugaryuk » Sun Apr 05, 2015 3:45 am

chevyart wrote:take float bowls off, and turn upside down and the bottom of the float bowl should be level(parallel with bottom of float bowl. if it isnt, adjust it with the adjust nut on needle and seat. this should get you very close to being right on, and then check with motor running and gas should just be trickling out bottom of sight plug hole. do this with car on level ground.. i have even done this with the motor off, by just rocking car slightly and the gas will overflow slightly out bottom of sight plug hole. if it does this, you are close to being right on. art


Thanks for the info, I've heard about this method but never tried it out, sounds easy enough. Carbs are off at the moment, cleaning up the motor before the season starts up in a few weeks! The secondaries were set to 1/2" .
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