Re: 440 Six Pack Carb Plugs
[Re: Tony440]
#2996920
12/20/21 06:36 AM
12/20/21 06:36 AM
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Joined: Jan 2003
Posts: 6,571 Abilene, Texas
fastmark
master
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master
Joined: Jan 2003
Posts: 6,571
Abilene, Texas
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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.
Last edited by fastmark; 12/20/21 06:58 AM.
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Re: 440 Six Pack Carb Plugs
[Re: Tony440]
#2997224
12/21/21 03:17 AM
12/21/21 03:17 AM
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Joined: Feb 2006
Posts: 608 TN
1DGEMAN
mopar
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mopar
Joined: Feb 2006
Posts: 608
TN
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What size are the kill bleeds? They control when the end carbs open. The springs control how fast they open.
Real Men shift for themselves
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Re: 440 Six Pack Carb Plugs
[Re: 1DGEMAN]
#2997227
12/21/21 06:58 AM
12/21/21 06:58 AM
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Joined: Jan 2003
Posts: 6,571 Abilene, Texas
fastmark
master
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master
Joined: Jan 2003
Posts: 6,571
Abilene, Texas
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What size are the kill bleeds? They control when the end carbs open. The springs control how fast they open. 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.
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Re: 440 Six Pack Carb Plugs
[Re: Tony440]
#2997307
12/21/21 01:51 PM
12/21/21 01:51 PM
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Joined: Nov 2006
Posts: 2,265 IL
furious70
top fuel
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top fuel
Joined: Nov 2006
Posts: 2,265
IL
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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)
70 Sport Fury 68 Charger 69 Coronet 72 RR
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Re: 440 Six Pack Carb Plugs
[Re: Tony440]
#2997561
12/22/21 12:23 PM
12/22/21 12:23 PM
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Joined: Oct 2007
Posts: 743 New York
R/T1968R/T
super stock
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super stock
Joined: Oct 2007
Posts: 743
New York
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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.
Last edited by R/T1968R/T; 12/22/21 12:32 PM.
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Re: 440 Six Pack Carb Plugs
[Re: Tony440]
#2997709
12/22/21 10:47 PM
12/22/21 10:47 PM
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Joined: Jul 2011
Posts: 972 Chicago
PurpleBeeper
super stock
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super stock
Joined: Jul 2011
Posts: 972
Chicago
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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.
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
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Re: 440 Six Pack Carb Plugs
[Re: 1DGEMAN]
#2997717
12/22/21 10:59 PM
12/22/21 10:59 PM
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Joined: Jul 2011
Posts: 972 Chicago
PurpleBeeper
super stock
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super stock
Joined: Jul 2011
Posts: 972
Chicago
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What size are the kill bleeds? They control when the end carbs open. The springs control how fast they open. 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
Last edited by PurpleBeeper; 12/23/21 07:13 PM.
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
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Re: 440 Six Pack Carb Plugs
[Re: jcastle1]
#2997733
12/22/21 11:46 PM
12/22/21 11:46 PM
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Joined: Mar 2011
Posts: 3,178 Michigan
A727Tflite
master
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master
Joined: Mar 2011
Posts: 3,178
Michigan
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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.
Last edited by Transman; 12/22/21 11:49 PM.
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Re: 440 Six Pack Carb Plugs
[Re: Tony440]
#2997872
12/23/21 01:47 PM
12/23/21 01:47 PM
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Joined: Jan 2003
Posts: 3,687 South San Francisco, Ca
70sixpkrt
master
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master
Joined: Jan 2003
Posts: 3,687
South San Francisco, Ca
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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. 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.
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Re: 440 Six Pack Carb Plugs
[Re: 70sixpkrt]
#2997887
12/23/21 02:22 PM
12/23/21 02:22 PM
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Joined: Jan 2003
Posts: 4,807 Moved to N.E. Tennessee
GomangoCuda
master
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master
Joined: Jan 2003
Posts: 4,807
Moved to N.E. Tennessee
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if you open the throttle quickly to say 1/3 to 1/2 way they open imediately, 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?
Last edited by GomangoCuda; 12/23/21 02:37 PM.
In theory, there is no difference between theory and practice. In practice, there is.
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Re: 440 Six Pack Carb Plugs
[Re: GomangoCuda]
#2998133
12/24/21 09:35 AM
12/24/21 09:35 AM
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Joined: Jan 2003
Posts: 6,571 Abilene, Texas
fastmark
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master
Joined: Jan 2003
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Abilene, Texas
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if you open the throttle quickly to say 1/3 to 1/2 way they open imediately, 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.
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