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Carter BB Sizes & CFM Ratings


55 Fargo

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A couple weeks back discovered that the carb I installed about 4 years back on my engine, is a very small CFM rating 1 9/16 throttle bore, and venturi 1 1/4. Can't remember where I got it from, but it's CFM rating is pretty low, below 100.

I have another truck carb, throttle bore 1 11/16, venturi 1 17/32. The CFM rating and jettting is in upwards to about 170 CFM.

The next short while will install and see what this does with my engine and performance.

I plan to go triple carb AoK intake and split exhaust in the New Year some time. I am thinking the 3 carbs, although more CFM for full throttle, should give a way better balance fuel distribution that a single or even dual.

But am going t install this bigger carb to see what happens if anything.

There are many different CFM ratings for the Carter BB carbs, some very small, some quite huge...

Edited by Fargos-Go-Far
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I think you are right about the 3x1 setup being a better balance than the 2x1 setup because you can run progressive linkage so the two end carbs only come in at WOT.

 

I just bought a Edmunds 2X1 intake for my flat 6 226 Ford,and most people seem to run two of the stock 8HA 1 barrel Holley carbs. That might work good on racing setups,but basically stock street engines  have to be overcarbed using 2 carbs designed to feed the same engine as a single carb setup.

 

I think I am going to make two adaptors,and use a pair of progressive 2 brl Holley-Weber or Carter-Weber carbs like were used on pre-smog 4 cylinder engines of about 100 cu in displacement. I think they will work well with a 2x1 setup where they both work all the time.

 

Yes,I know they were meant to be used on OHC  high-reving 100 cubic inch engines and not low-revving flatheads,but I am thinking I can tune the Webers to deliver slightly less gas when the secondaries kick in. Plus I plan on eventually putting split exhausts and a 3/4 cam in the engine before it's all over,along with a shaved head and electronic ignition.

 

I think this has the potential to be a really good setup for flat 6's. Anybody disagree,and why do you disagree,before I start spending money?

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I think you are right about the 3x1 setup being a better balance than the 2x1 setup because you can run progressive linkage so the two end carbs only come in at WOT.

 

I just bought a Edmunds 2X1 intake for my flat 6 226 Ford,and most people seem to run two of the stock 8HA 1 barrel Holley carbs. That might work good on racing setups,but basically stock street engines  have to be overcarbed using 2 carbs designed to feed the same engine as a single carb setup.

 

I think I am going to make two adaptors,and use a pair of progressive 2 brl Holley-Weber or Carter-Weber carbs like were used on pre-smog 4 cylinder engines of about 100 cu in displacement. I think they will work well with a 2x1 setup where they both work all the time.

 

Yes,I know they were meant to be used on OHC  high-reving 100 cubic inch engines and not low-revving flatheads,but I am thinking I can tune the Webers to deliver slightly less gas when the secondaries kick in. Plus I plan on eventually putting split exhausts and a 3/4 cam in the engine before it's all over,along with a shaved head and electronic ignition.

 

I think this has the potential to be a really good setup for flat 6's. Anybody disagree,and why do you disagree,before I start spending money?

No I would not run "progressive" linkage for a 3 carb set-up, 3 Carter B&B for me, jetted correctly. Again better fuel/air to each of the 3 siamesed intakes. 

With a 3 port intake engine, an the intake with 1 carb in the middles, cyls 3/4 will get the most, while 1,2 and 5,6 will be less, not very balanced, but of course has worked well for many years on millions of engine for bone stock set-ups.

It has been a common report of better fuel economy on multi-carb setups on inline 6 cylinder engines. The important thing, is matched carbs, and carbs and linkages synced properly too.

I am not saying progressive carbs are not a good thing, but for what I am planning, it will Carter BBs, synced linkage.

That Ford should have better fuel economy, better throttle response, if well synced and with correct jetting..

post-107-0-09867700-1451175911_thumb.jpg

Edited by Fargos-Go-Far
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I think you are right about the 3x1 setup being a better balance than the 2x1 setup because you can run progressive linkage so the two end carbs only come in at WOT.

 

I just bought a Edmunds 2X1 intake for my flat 6 226 Ford,and most people seem to run two of the stock 8HA 1 barrel Holley carbs. That might work good on racing setups,but basically stock street engines  have to be overcarbed using 2 carbs designed to feed the same engine as a single carb setup.

 

I think I am going to make two adaptors,and use a pair of progressive 2 brl Holley-Weber or Carter-Weber carbs like were used on pre-smog 4 cylinder engines of about 100 cu in displacement. I think they will work well with a 2x1 setup where they both work all the time.

 

Yes,I know they were meant to be used on OHC  high-reving 100 cubic inch engines and not low-revving flatheads,but I am thinking I can tune the Webers to deliver slightly less gas when the secondaries kick in. Plus I plan on eventually putting split exhausts and a 3/4 cam in the engine before it's all over,along with a shaved head and electronic ignition.

 

I think this has the potential to be a really good setup for flat 6's. Anybody disagree,and why do you disagree,before I start spending money?

I can not speak to your ford, but for a flathead mopar you definitely do not want progressive linkage.  Here is a high level view of why, some of which I see someone already touching on.

 

With a flathead 6 cylinder mopar of the 23 1/2" USA small block or the 25 1/2" Canadian big block variety, both have 3 intake ports entering the block that feed

the 6 cylinders, commonly known as Siamese ports.  if you put 1 carb in the middle of the intake, and assuming all 6 cylinders are  of equal compression, you will

be feeding more fuel to the middle Siamese port than the outside two.  I wont go into the details, but actually as you accelerate the balance changes slightly.

 

When you put a 3 carb intake on a flathead mopar and if all three are exactly the same, you provide a better fuel and air mixture with a better balance into each of the 3 Siamese ports.    The concept of progressive linkage, say on a v8 which has a balanced plane going into the 8 cylinders, is  that the more your press on the throttle

the more fuel you will want, and  you can introduce more carbs.  But with the 3 intake port system, you will actually get better fuel economy at say 55 mph with 3 carbs than 1, and you actually require less throttle to achieve it.

 

So while progressive carbs work well on many engines, and most v8s are good examples, for a flathead mopar progressive carbs are not a good idea, in terms

of adding more carbs to the mix.  The progressive carburation for a 3 carb flathead mopar is called the throttle pedal. Push it and you progressively put more fuel 

into the engine, but each carb needs to be putting in the exact same amount of fuel.

 

Now back to the ford.. that I cant tell you.  On a side note, the carter weber that was designed and introduced for the 170 ci slant six, was feeding more less

cubic inches of motor, but also had the advantage of a reworked intake port situation that saw long runners all equally feeding each of the 6 cylinders.  They work

well on the slant 6, but are definitely a compromise for a flathead 6 over a carter ball and ball, in my opinion.

 

 

Tim

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>>Now back to the ford.. that I cant tell you.  On a side note, the carter weber that was designed and introduced for the 170 ci slant six, was feeding more less

cubic inches of motor, but also had the advantage of a reworked intake port situation that saw long runners all equally feeding each of the 6 cylinders.  They work

well on the slant 6, but are definitely a compromise for a flathead 6 over a carter ball and ball, in my opinion.

 

 

Tim<<

 

Tim,I al talking about progressive 2 brl CARBS,not the linkage. The linkage will be straight and each carb will be feeding 3 cylinders. Normally the smaller throttle bore on each carb will be in operation,but the larger one comes into play at around 3/4 throttle.

 

And each carb will be one that was originally put on a engine of roughly 100 cubic inch displacement

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>>Now back to the ford.. that I cant tell you.  On a side note, the carter weber that was designed and introduced for the 170 ci slant six, was feeding more less

cubic inches of motor, but also had the advantage of a reworked intake port situation that saw long runners all equally feeding each of the 6 cylinders.  They work

well on the slant 6, but are definitely a compromise for a flathead 6 over a carter ball and ball, in my opinion.

 

 

Tim<<

 

Tim,I al talking about progressive 2 brl CARBS,not the linkage. The linkage will be straight and each carb will be feeding 3 cylinders. Normally the smaller throttle bore on each carb will be in operation,but the larger one comes into play at around 3/4 throttle.

 

And each carb will be one that was originally put on a engine of roughly 100 cubic inch displacement

 

my apologies for misunderstanding what you were meaning. I know the carter webers I have seen that were for the slant six, are into the 2nd barrel way way

before 3/4 throttle. 

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timkingsbury wrote: 

 

>>my apologies for misunderstanding what you were meaning. I know the carter webers I have seen that were for the slant six, are into the 2nd barrel way way

before 3/4 throttle.<<

 

Thanks,I didn't know that. I was just assuming they worked like the Holley-Weber carbs.

 

Then again,maybe most do,because most of them were used on GM OHC 4 cylinder engines,like Vegas and the other subcompacts.  Tiny little engines that rev up pretty high.

 

Maybe I should stick with the Holley-Webers ,like this one...

 

http://www.ebay.com/itm/311510676466?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

that were made for Pinto's and Escorts?

 

I have been thinking about sticking to carbs made for pre-1973 engines to avoid all the complications of modern smog carbs.

 

Anybody have any real world experience with these on flat 6's?

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timkingsbury wrote: 

 

>>my apologies for misunderstanding what you were meaning. I know the carter webers I have seen that were for the slant six, are into the 2nd barrel way way

before 3/4 throttle.<<

 

Thanks,I didn't know that. I was just assuming they worked like the Holley-Weber carbs.

 

Then again,maybe most do,because most of them were used on GM OHC 4 cylinder engines,like Vegas and the other subcompacts.  Tiny little engines that rev up pretty high.

 

Maybe I should stick with the Holley-Webers ,like this one...

 

http://www.ebay.com/itm/311510676466?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

that were made for Pinto's and Escorts?

 

I have been thinking about sticking to carbs made for pre-1973 engines to avoid all the complications of modern smog carbs.

 

Anybody have any real world experience with these on flat 6's?

 

Sorry to go off topic, but the Carter Weber Motorcraft 740 2 barrel from a 1983 Escort worked very well for me.. They were for the 1.6L motors (about half of my stock 3.3L or 201 c.i. motor), which I got from Langdon's Stovebolt. I was running 2 on my Sharp intake, but went with 2 stock 1938 B&B carbs and a Nicson intake for looks/nostalgic reasons.

 

http://www.langdonsstovebolt.com/store/#!/Carter-Weber-Carburetor-With-choke-pigtails/p/1222026

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I might have mentioned before but my 50 Dodge meadowbrook came with the BB, and since it has a fluid drive 3 speed manual, I understand it should have had the Stromberg with the throttle damper. Is there a damper I can use on the BB?

Aside from the damper, though, is the BB any better or worse than the Stromberg?

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Carter carbs can have the throttle damper too.A Carter D6P1 or P2 is probably what you need for your Dodge with 3 speed and Fluid Drive using the slow closing throttle dash pot.

IMO Carter carbs are easy to get parts for and are a better built carb.

The side levers on Strombergs are prone to coming loose and are very hard to do a long lasting proper repair.

The loose side lever can cause erratic idling speed issues.

Edited by Dodgeb4ya
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