So the idle on my car is at 15:1 AFR, and the screws are 2 1/2 - 2 /34 of the way out. I have the metering block over at a long time Holley guys shop, and he was going to enlarge the passages by .003, but they are not where they usually are on these metering blocks. To get to the passages, is it through the brass plugs on the bottom of the block? And if so, it looks like those are not going to come out easily. Where do I get replacements?

And is this what I need to do to be able to richen it up at idle, and have the screws in a reasonable place?

Mick, have you tried adjusting the mixture screws in the baseplates of the end carbs? Backing them out maybe 1/8 turn each will make a big difference and take some of the load off your center carb. I have set up more than a few 6 paks and even with big cams, I've never had to open idle passages in the center carb. Good luck!

VERY good advice.

Also, I am not aware of any metering block idle mixture passages under the metering block behind plugs???

There are main circuit passages behind the power valve at 3 o'clock & 9 o'clock that can be enlarged per the old Direct Connection book, but I don't recommend doing it. There are also some holes up in the top corners (name?) that can be enlarged too, but again I don't recommend it.

I know you have that big stroker hemi six pack, so maybe consider Promax parts instead of modifying stock pieces. You can get adjustable metering bodies & adjustable metering plates.... but try the outboard idles screws first like Lee says. THOSE are behind lead plugs on the front of the baseplates for the outer carburetors. Hope this helps.

Best idle on a small block Sixpak setup with an XE268 cam ended up with the mixture screws on all 3 carbs out 1 5/8 turns. Covering the corresponding air bleed one at a time will tell you which direction to go with the mixture screw. Never had to drill anything.

I have done that following the writeup from Dayclona, and have the end carbs, as far as I can tell, adjusted properly, in that when I cover the air bleeds one at at time, there is no change in the idle. There was when I first put the carbs on, so I know there was a change.

What is wrong with that I like to see above 14.5 AFR at idle when warm or hot to help keep the plugs clean
My old pump gas Duster 6 pack set up ran at or above 15.2 AFR at idle and low part throttle high manifold vacumme cruise up to 2300 RPM That rascal flat rocked

Damn good question! It started with me asking a couple of very experienced engine builders why my car stinks so bad at idle. I thought running rich would make it stink, an they both said, "because it's running too lean."

So, in an attempt to richen it up to see where that would get me, and knowing that for a Holley, almost 3 turns out on the idle screws is not optimal, I was attempting to get the idle screws to a more normal position, to give a range of control over the mixture.

To see if enrichening helps the idle air fuel ratio helps you gain better control of the idle mixture try using some very thin wires formed like a J stuck upside down into all six idle air bleeds
Let us know your results

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Damn good question! It started with me asking a couple of very experienced engine builders why my car stinks so bad at idle. I thought running rich would make it stink, an they both said, "because it's running too lean."
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My EFI car smelled bad at idle as well. It has a pretty healthy roller cam in it. That was with an oxygen sensor feeding back to the ECM.

I welded a pair of metal matrix, racing catalytic converters on it and the problem was solved. It didn't affect the power output either.

Well, here's a fun one!

I just got a call from Holley, and apparently some of these metering blocks are making it down the line, WITHOUT the idle restrictor passage being drilled out! And mine is one of them...

So, they are sending me a new metering block, and I'll take it from there.

Sigh...

I've drilled and tap (6x32)several Dominator body to add idle and transition fuel restrictors to help lean them down to make them have 14.25 or leaner at idle or on the low part throttle opening on the transition circuits
I've never had a motor smell rich from being to lean at idle
Maybe I should get my old LM1 system hook up on my 1966 Dodge street car and experiment some with it to learn some more

This is an interesting idea!

WOW! GREAT thing you called Holley.... good job.

The stench from burning lean doesn't smell anywhere near the same as burning rich.

Burning rich burns your eyes where lean just stinks - it even smells hot - has a "burning" smell but doesn't burn your eyes. At least the ones I have been involved on.

Good deal on holley sending you the new metering plate, its always been hit and miss on the idle restrictors. Whoever is helping you is right, center needs more fuel to get to 1 turn out on the idle screws with proper air fuel reading. You may also need smaller main jets after doing that. If you look up the venturi size of the center and use a double pumper front plate that matches that venturi,600 or 650 I think, that works too and most old double pumpers have idle jets down low where you can drill them.

So much for Holley quality control...You wouldn't think something like this would ever leave the factory...

when were the carbs originally bought?

bought new, last year or two.

If you want the latest technology in metering blocks,go here,you won't be disappointed!

http://getmgarage.com/products1.html

your lean description is what mine is like...

Hope you get it resolved.

For me, I have to tell you that you are the first guy that I have heard that has a lean six pack. Most everyone I have heard of or seen has always been stink rich.

That lean stench smell I describe - I usually smell it behind old school buses. Why - don't know.

Well remember, it's lean because they didn't drill out the idle restrictor passages! I'll see what happens when I get a correct metering block in there.

With 2 1/2 turns out to get a 15:1 idle, I assume with a properly working metering block I should be able to now set it where I want.

Get yourself a Promaxx metering block. They will set it up for you.
http://promaxcarbs.bizland.com/id1.html

I would go for that, expect I want to keep the stock look. I know I'm leaving a lot of horsepower on the table by a) having the six pack in the first place, and b) not setting it up optimally, but it's the novelty I'm going for.

Once I miss the extra horsepower of my 2X4 setup, (and I do already, just not enough yet), I'll go back to that. But for now, it's just cool having an air cleaner that reads...

"HEMI Six Barrel"

Are you going to set up the carbs properly or just wing it and then ask questions?

Did you know that Tom Hoover spoke very highly of a six pak on a hemi as the fuel distribution was wayyyy much better than the 2x4 set up? I thinks it's humorous with all the talk that a few ponies were left on the table with the +6 vs 2-4s or a big fat 4bbl when a drag race would confirm that six paks rule!.

You don't see the metering block with the air cleaner on.

No, I did my research first, installed them following some specific instructions I got here on the board, and now am asking questions for the small issues I'm having problems with.

That was one of the reasons I did it, was talking to Tom Hoover about it a few years ago at MATS. But first of all, that was a 426 he was talking about, not a 540. Then there is the fact that at 4bbl ratings, the six pack flows 935 cfm, where the two Edelbrocks I have flow 1300. Then there is the dual plane design of the 6 pak manifold as compared to the single plane Stage V dual 4 I use, which dyno'd by FHO produced 40 more HP than a stock manifold. And yes, setting up a set of drag 6 pak carbs with all 500 CFM carbs may put it back in the range of a single or two 4's, but probably not with that manifold. So this really is in no way and apples to apples comparison.

So yes, it is down on power, and would lose miserably on the track to my other setup.

Ok, the conclusion to all this. Got the new metering block from Holley, same result. Probably my fault, but I reminded them, (may not have told them in the first place, thought I did), that I'm dealing with a 540, and they said, Oh, in that case there is nothing we can do for you. This is designed for a 440, and will supply it well, but we can't do or say anything about a larger displacement engine.

Called ProMax, and they said "Yep, that is what our metering blocks are designed for." He also said the six pack metering block is an odd duck, in that it doesn't have an idle restrictor passage in the usual place, which started all this.

So I live with it, or get a Promax block, as Ricky suggested.

All I wanted to do was clean up a stinky idle. I'll live with it for now...

I wouldn't run too lean. You could wash out some cylinders.

Some times you can not get the carb down to the idle circuit and still have enough air to keep the car running, I drilled a small hole in each butterfly plate to allow additional air flow so the car will stay running while down on the idle circuit.

how big is the cam and what is the LSA ?
if it has alot of overlap you might be stuck with a stinky idle...

also you have three carb to adjust idle mix on?? can you richen the outboard carbs up a bit and get the center carb a little more in line with traditional settings??

i guess as a test, you could always put some thin wire in the idle air bleeds, readjust idle mix to where it likes it and see if the exhaust is still stinky...

Mick if decide to pull the Sixpack off, let me know.

I'll swap manifolds one of these days, but will keep the six pak setup. No sense in getting rid of it, it's a fun novelty! But I will let you know.

I have it farther down, in the 14+ range, just turns the screws farther out.

I'm just going to live with it. There are other things that need attention, this is just more of a nuisance than anything else.

I didn't expect it to take this much time and energy, but since it is what it is and doesn't harm anything, it's good enough.

If you hate the stinky smell switch to 101 low lead AV gas,you'll love it then !!

Is that a sarcastic "you'll love it"? Besides with what I imagine to be $7-10 / gallon prices, I'm not sure about that!

If you have a large overlap cam you should be focusing on idle quality, not what an O2 meter is reading. It simply does not read right. If the O2 meter is reading 15:1 the the combustion charge AF ratio could still be far too rich. Some have reported as high as 18:1 meter reading at best idle quality w a big cam

Not sarcasm,fact.All I've ever ran in my sixpack Superbird and wagon since 1992,airport is 10 mi over the mountain,$4.35 gal.

Do you know about the Federal law restricting using leaded fuel of any type on any public U.S. roads, freeways or highways in all of the U.S.? If not be aware of it, it carries a $10,000 for the first offence
I can tell you that every law enforcement agency in California that I've talk to or heard about are aware of it and they know the local courts get to keep all of the fine money from that citation
I was warned by a San Bernardino County sheriff about that back n the 1990s when he saw one of my old race cars with current tags at the old LACR race track, he assumed I drove it on the street regularly, which I hadn't done in his presents at that time, he was a drag racer also The smell gives it away

Make it idle happy. The AFR will land where it lands.

Every time it misfires, all the O2 that didn't get used for combustion goes out the exhaust and a big overlap cam misfires A LOT at idle. That's why an engine idling pig rich can indicate 18:1 dead lean.

Kevin

My FAST portable wideband wouldn't even read my air-fuel ratio at idle. It's beyond it's range, because its too rich. I changed my cam and compression, and am a day or two away from seeing if it will read it with this one.

Is everyone setting idle mix by adjusting to highest idle speed or vacuum reading?

after I threaded the IFR's in my metering blocks and dropped the IFR size down, I figured I would be close to the typical 1.5 turns out from seated so I set them up initially at 1.25 turns out.
It started and idled OK, kinda bumpy, kinda stinky.

after it warmed up all the way I started leaning them out, idle goes up, smooths out. keep going around the carb, a tad leaner every time. Ended up at just a touch more than a half turn out.

I was thinking wth, after all this work these should be further out, then I figured well, I dropped the IFR down but the I didn't touch the idle bleeds and they are roughly .067", pretty small.

The idle smoothed out, smells much cleaner (still smells like it has some overlap), I had close the blades to drop the idle back down...it starts up with just a touch of the key when it's warmed up...I'm just gonna worry about other things now and leave the idle screws where the motor likes them.

Yeah, got it. I usually do it with a vacuum gauge. Will start again there and see where it ends up.

Cam is 248/255, .604/.582 LSA 112 on a 110 centerline.

That doesn't seem big enough to be the cause of my idle stink!