How to Adjust the Holley Idle Mixture Screws

This is a YouTube Short for the full video where I installed a new Holley Carburetor and I needed to get it dialed in on my 1966 Mustang Fastback.

There are quite a few steps to do during the process of setting up a Carb, but the YouTube Short videos are limited to 60 seconds, so this is only part of it.

The car is a 1966 Mustang Fastback with a 347 Stroker and T5 transmission.

Shot with GoPro Hero 9 with the Media Mod, edited on Davinci Resolve 17.
Gear I use:

Credit for the music in the video:
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Epidemic Sound
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#krusebuilt
#kruseview
#Mustang
#1966
#fastback

[BPattB]

I like how your shorts randomly pop up in feed. I was just setting the idle on the Holley 650dp i ended up with. Maybe because i only have 10inchs at idle i was happier setting to the highest RPM

[STKGarageCanada]

I did the same and then my afr showed 13.3. Then I adjusted more, still kind of highest vacuum but could get afr 14. Afr is the best gauge that I installed, now tuning carb jets with it I was able lower my 0-60 for a sec and I'm not done yet.

[ceasergert]

Thanks for posting this
It has helped very much

[daveburn]

Advance your timing. This will also raise the vacuum. Vacuum helps atomize the fuel and keeps it suspended. It's not uncommon to have about 30 degrees of advance at idle, especially with heavy cams. This will also help the lumpyness and wanting to stall at idle.

[tonyjackson]

What port connectiom did you connect the gauge.

[ExecMoose]

Well this was over half a year ago, but did you ever get it dialed? Mine reads steady at 20 with a mild cam. I had to bump the timing up quite a bit, and that's what this looked like as well. Also your fuel pressure looks to be set super low, but I also have no idea if you have a mechanical pump, and if that's what they run.
Took me forever to listen to my gauge saying "late ignition timing" and think maybe I just need to advance it lol.

[DieHolden]

That's a little cheaper than doing it with a wide band oxygen sensor. You might get it a fuzz more precise with an oxygen sensor but that looks good to me.

[nicholasjarosch]

I heard that you set the idle so that the transfer slots are just a small square and then adjust the timing and mixture screws for the highest vacuum

[SeanNeuhaus]

How come ur fuel pressure is 2lbs u need 5to7 with a carb

[Personalsubcounter]

I need a vacuum gauge. Where did you buy that one ?

[curtisimo]

I get the highest vacuum on my 351C when my timing at 53 degrees advanced lol.

[dreamingcode]

I'm a total newbie, so it would have been helpful to know where are you plugging the vacuum into the Holley Carb?

[bobbydelamar]

I want to do this but I can't even get my car to idle. I have to open the throttle to get it to stay running.

[SeanNeuhaus]

I had a similar situation couldn't adjust anything I tinkerer with everything by 1000 ft at the dragstrip I had 2lbs of pressure short story got some bad race fuel vary uncommon left over from the previous year ....big mistake anyhow leaned out burned the block between 3n5 cylinder changed pump filter system brand

[KurtKoster-st]

Mixture screw's and timming all play a part

[LC-gouh]

I can do all that without a gauge. You just go by sound and feel.