440 Six Pack Carb Plugs

Hello, does anyone know an easy way to get the lead plugs out of the out board carbs to access the mixture screws on the Holley 2300 series front and rear carbs? My 440 idles fine and the out boards open but bog. I have the black springs in the diaphrams. When they open at part throttle they don't seem to pull fuel through the venturies. I had the carbs on a 383 and they worked great, but on the 440 the same carbs seem to spike lean at part throttle. Thanks in advance for any replies.

They are really thin and soft. Take a 1/8" bit and drill VERY carefully only through the thin top, then take a hook pick and pull the cap out. really easy. Don't be surprised the adjusting screws are stuck in there. try not to break the tangs off, it then becomes a process to remove the brass screws. after 50 years the original cork material around the brass adjusting screw becomes like concrete.

Thanks I'll try that.

Be careful with those screws. If your carbs are very old and the cork gasket are hardened, you will break the brass screw. Then you are in trouble. I remove lots of those in carb restoration. First I remove the hardened gasket with a pick. I now have a lathe so I’ll make a special tool to clean them out faster, but a needle pick will work. You may need to soak it first in wd40 or carb cleaner.

The carbs are very old. They are running on my 440, but I'm sure you are correct. The screws are probably frozen. I will do as you suggested. Thanks for your help.

If you're not working on a "correct" car, there is a replacement base available with angled idle jets.
You'll only need it for the rear carb if only one gets boogered up trying to repair it.

DAMHIK

Have one on our Dodge, works great.

Joe

So the cork gasket is the only issue ?

And once you get that out the screw usually is free?

Or do the threads need to be lubed up too ?

I have an old set and am getting ready to flog them.

If you look at the bottom of some baseplates right where the idle screw goes in it sure looks like holley dimpled the base after the idle screw was set to lock it. Rumor has it that that really sticks them in there, I think drilling those would help relieve pressure. Soaking, lube and a small sleeve that fits over the idle screw so one side does not break off will lead to success.

I’ve heard the rumor too about that “dimple” . I’m not certain but that it may be cast into the base when it was made. I discussed that rumor with Bill Overcash when I first started using him to restore the carbs on my Superbird. He never found it necessary to drill out that dimple. Neither have I had any problems and I’ve been messing with six packs since 76. After Bill passed last year, I decided to start restoring carbs. So far, I’ve taken apart about 30 end carbs and have no problems getting them out if I’m careful. Carbs in better overall condition are easier. The old corroded carbs take more care. I get the gasket out and soak it with carb cleaner and/or wd40, but I’m still very careful. I have gotten them out on several that customers have sent into me already broken off. If you do break one off, give me a shout. I bought all of Bill stuff so I have some spare ones.

Thanks to everyone for the replies. Do the gaskets need to be replaced after they are removed?

Yes they do, common Holley item.

If you mean the cork gasket around the needle, then yes. They come out dried up and in pieces. It’s the same gasket as the center metering block screws.

If me I would work with the idle fuel feed restriction, 383 pulls fuel different than the 440 even using same cam. Ends carbs have no squirters so it has to be richened up a little in that restriction, like you said it idles good and moving the needle let’s air and fuel in, you only need fuel.

outboard air bleeds plugged.........?

This sounds like what I really need to do. Can you please explain the best way to address the idle feed restriction, and where it's located? I have heard of this before. Thanks for your advice!

Also I neglected to mention I have the Promax metering plates with 84 jets installed.

This “idle air bleed” modification is something that needs to be left to a serious professional. You start drilling out holes you better make sure you know what you’re doing. It’s not like this new carbs with the changeable air bleeds. Check to see if they are plugged up first. If you install a dual sensor wide band o2 system on your car, it will help. There are gifted individuals who can tune by feel, so to speak, but they are not new at this. Get the screws turning and get a wide band O2 unit and play with the carbs. It will help.

Thanks again to everyone for the replies. So to recap, does everyone feel that the out board idle mixture screw settings may be the reason the outboard carbs open but bog(lean) and even at cruising speed the car seems to bog when the out boards open. I've tried everything to remedy this to no avail. I don't understand why these same carbs would work so well on the 383, but behave like this on the 440. If changing the out board idle mixture screw settings, from where they are set from the factory would fix this than I'm all for it. But I would hate to break off one of the screws and open a can of worms. Is there anything else that could cause what seems to be a lack of fuel to the outboard carbs as ther open?

float too low . wrong spring in outboards. pluged kill blead orfice . wrong or bad power valve . incorrect timing . old bad fuel .

pluged idel circuts . bad gaskets someware .


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If it bogs with the black springs, just make sure it’s not the center carb. Those black springs open very late. Disconnect you vacuum line to the end carbs and plug it. See if it still bogs. The end carbs idle screws are mainly for idle mixture and not for off idle power. I think you have something else wrong.

I did as suggested and disconnected and plugged the vacuum lines to the out boards, and the car runs fine, no lean bog. So it seems like it is the out boards. At cruise speeds the outboards open you can hear them but the car doesn't speed up. It's certainly a lean condition lack of adequate fuel when they open. All I did was transfer all 3 carbs from the 383 where they worked great to the 440. I thought they may have needed to be richened up so I added the Promax jet pates with 84 jets, and it still behaves the same. I'm stumped. Thanks to everyone for the suggestions.

there’s something else wrong. The screws in the end carbs are just for idle. As soon as the end carbs open, they should be drawing fuel from the main circuit. Check fuel pressure and make sure your fuel filters( inline or end the inlet of the outboard bowls) are not plugged up. I have a question. What oem end metering plates did you have in the carbs originally. The different plates have different size holes. For instance.
4393 front no 6178
Pass. .080
Dr. .085

4394. Rear no 6180
Pass .084
Dr. .092
Both of these plates have a .034 air bleed in the plate

I’ve got some more notes at the shop but the plates that I checked and recorded on my phone were some old direct connection tuning plates and may not be the same as the oem no. 34 and 35 but here they are.

Front no 34
Pass. .088
Dr. .090

Rear. No 35
Pass. .085
Dr. .093

These plates have .037 air bleeds which will lean the mixture slightly.

Remember. These are actual sizes in inches. The Holley jets are numbered differently. Check the chart you got from Promax. I don’t have it here at my house. If you still have problems, shoot me a pm and I’ll give you my number and you can call.

Hi Fastmark, thanks for your reply. The original metering plates in the out boards are marked 35. I purchased all 3 carbs new back in 1985. They were reproduction 1969-70 auto carbs. Last year I installed the Promax jet plates and per their suggestion installed the 84 jets in the front and rear. This has not fixed the issue. I do have a new inline filter, and when I rebuilt the carbs last year I made sure that everything was cleaned and blown out. There isn't any inlet(brass) filters on the carbs. That is the way they came from Holley. Unfortunately we just got our first snow yesterday, so I think any testing will have to wait until the roads are salt free again. I really appreciate your help. I don't understand why these carbs worked so well on the 383, and are so different on the 440. I agree that the idle mixture screws on the out board carbs should not affect this issue.

What size are the kill bleeds? They control when the end carbs open. The springs control how fast they open.

I don't know what size the kill bleeds are. Where are they located? I haven't modified them, so they are stock. I have the Promaxx jet plates installed

If he bought the carbs New, I’m going to assume the kill bleeds have not been modified. When I raced my car, I had a fuel pressure guage that I could watch as I went down the track. If the fuel pressure dropped, it would start to slow down. The last six pack I built and tuned had a Carter that would make about 6 lbs. it worked great. Do you have the same fuel pump on the 440 as the 383? I started out with the black springs and they did not open much at all. Have you tried quicker springs? I’m a believer in a wide band O2 sensor to tune with. It really helps on a six pack.

The fuel pump is for a 440 six pack, I believe it was rated for 6.5 PSI. I installed it last Spring thinking that may have been the issue.

I don't have 6 pack experience but I can echo how helpful it is to have fuel psi and WBO2 data either logged or visible as you're driving and experiencing such issues. Even just temporarily hanging a gauge on the windshield wiper so you don't have fuel in the cabin (this assumes a later C/B or E body hood style)

There was a kit and a tool to do the end carb idle screws. I did it on mine. Still hard to adjust, but its possible. As for the metering plates you can actually plug or thread the metering plates like this.

or this

To answer your question....you can simply poke an ice pick or tiny screw driver into the center of the plug and pry it out.. piece of cake. I've heard of putting a propane torch to it and I'm 100% sure that would work perfectly and not do any damage to the base (note....PROPANE torch), but yeah, it would work. However, i don't think the front/rear idle mixture screws are your problem....not to metion if you have factory carbs, they're probably frozen in place.

Anyway, as you figured, you're running lean when you floor it. You have the black outboard springs (stiffest I think or maybe 2nd stiffest). Lean knock is too much air vs. too little fuel. With those stiff outboard carb springs "it ain't too much air": unless you've got a nasty vacuum leak somewhere (check). So, that leaves too little fuel. Check the squirt on squirter. Check to see if the accelerator pump cam is worn. See if you can adjust for a bigger/longer squirt with an accelerator pump cam change (or position change.... position 1 vs position 2).

Fatten up that accelerator pump squirt and let us know if it still bogs.

This may be it. I can't remember the name, so maybe it is the kill bleeds ??? I'm running those Promax outer plates too.

Ok, image this.... If you have a fuel bowl off of an outer carb and your looking at the facotry metering plate, there are two small holes at the top which are often drilled out in old school tuning. Anyway... the Promax plates have tiny, tiny,, tiny little hex screw "jets" that screw up into their plates. Nobody every talks about those. Anyway, the ones that come with the Promax plates are WAY bigger than stock (bigger holes in them). If you look on the Promax website, they only make vague reference to these "jets" . I researched this a ton to find out what the factory hole size was in stock metering plates. I called Promax and told them I wanted to match that factory stock hole size in my Promax plates..... and they had them. Not listed anywhere, but they had replacements in exactly the right size for cheap. Maybe those are kill bleeds and related to your problem?????

IGNORE ABOVE AND LOOK BELOW - KILL BLEEDS ARE BEHIND THE VACCUM POTS AS NOTED BELOW

More than likely its the carb to intake gaskets not allowing the butterfly on the vacuum operated outboards to not open. Had it happen on mine. Check that.

The kill bleed is behind the vacuum pot. Remove the front pot, and you will see a small hole horizontally intersecting the passenger side
Venturi. Take a piece of tag wire and run it in to this passage and you will see it enter the Venturi.
Rear carb has one as well. Not uncommon for people to press a BB in this passage.

Stock carbs do not have a plugged kill bleed. The opening in the Venturi is usually much smaller then the opening just behind the pot.

This kill bleed they are talking about is visible on the inside of the venture. Again, it only helps monitor the rate at which they open. The air bleed in the top of the end metering plate from Promax have to do with the fuel mixture. I’ve used his plates in as sold condition with staggered jets of 88 on dr side and 84 on pass side. Now, I doubt this is your problem but I thought I would mention it while we’re talking about air bleeds. In my shop right now. I have about 22 out board carbs in the stages of restoration. I have 4 of my own carbs in this bunch that are later issue 4365s and 2 are customers. I was checking things over before I started assembly of the 2 from my customer when I noticed the idle air bleeds On the outside of the throat were way too small. The main air bleeds looked about right. I guaged them both and they were both .037. They should be .039 main and .051 for the idle. I checked all my other 20 440 carbs of all number( both 69 and 70) and they were all the correct .039 and .051. This was a factory mistake that got out. I’m not sure if that much difference in the smaller idle air bleed could haven adjusted out with the screw but it would surely have been too rich. No I don’t think this is your problem but it certainly brings up the idea that the factory did make mistakes from time to time.

Thanks to everyone for all of the good suggestions. It still doesn't make sense to me why the same carbs would work well on a 383, and behave differently(lean bog) on the 440. The one thing I forgot to mention is with these carbs on the 383 they would open slower. When installed on the 440 they seem to open instantanously. In other words at cruising speeds, if you open the throttle quickly to say 1/3 to 1/2 way they open imediately, where on the 383 it would take approx. 1.5 to 2 sec. after hitting the throttle for them to open, and they would transition more slowly.

The kill bleed doesn’t monitor anything.

It’s a bleed. Close it off and the center carb vacuum provides a quicker opening to the end carbs.

Try to open the end carbs using a Mityvac with the kill bleed open versus closed.

As the end carbs start to open the Venturi effect helps speed up opening the carbs by “masking” the kill bleed leak.
With the kill bleed plugged the carbs open faster everything being equal.

No 2 engines are the same. Did both engines have the same cam, head flow numbers, Ignition, etc…? I would install an Air/fuel gauge and take it from there.

That should never happen. Check to make sure you do not have the six pack vacuum hose to the center carb switched with the one for the vacuum advance. The two ports are very close to each other. The port that comes out of the main body is the one you want. The port on the side of the metering block is for vacuum advance. The correct one is rearward of the other. Do you have a pic of the right side showing the hoses?

I agree. Those black springs don’t open very fast at all. As a matter of fact, the car I was tuning would hardly open them. It had a roller cam with about14-15 inches of vacuum at idle to work the power brakes. I delivered it with the short yellow springs and he really wanted them a little faster. I never got to change them before my friend passed away.

The Answer 99% for Sure - somebody else already mentioned it here already. Since the six pack setup worked fine on the 383 and now it opens so quickly the engine bogs on the 440.....the vacuum hoses are hooked up wrong. Look at your 3-way-Tee vacuum hose that connects all 3 carburetors. The hose for the middle carburetor should be connected to a nipple on the body of the center carburetor. I bet you $2 you've got that vacuum line connected to the nipple on the baseplate of the center carburetor....where the choke pulloff should be connected. THAT port at the base of the center carburetor has full manifold vacuum. Your outboard carburerors are being pulled open constantly and you're only noticing it when you floor the pedal. Check those hoses vs. a picture in a factory service manufal. Nipple on the side of the center carb goes to the 3-way vacuum tee. Nipple on the metering body goes to the distributor vacuum advance. Nipple on the baseplate goes the the choke pulloff. They're all the same size hose/nipples so easy to mix up.

Gentlemen, I will check the vacuum lines when I get back from vacation. This is a good suggestion and may be the problem, As mentioned even with the black springs installed the out boards seem to open way to fast. Everyone has been very helpful, and I appreciate everyone's input. I will keep you all posted. Thanks again, Tony