4bbl carb on flathead?
- Thread starter Flathead man2
- Start date
Flathead man2
Senior Member
When I do go with a 4bbl how much could I lean it out to make the engine run right but at the same time to have it run when I stomp on it? If I remember right ya cant lean them out very much and still have performance. I think generally three turns lean. I might be wrong. I'm goin to look at an engine later this month. It's a 52 merc engine 255 if I'm on the number.
flatjack9
Well-known member
The only real way to know is to use an A/F ratio meter. If the carb is sized right for the engine, you really shouldn't need much adjustment. The idle mixture is controlled by 2 needles and 3 turns is out of the question. Cruising A/F ratio is controlled more with main jets. Again changes of 1 or 2 sizes should be all that is required. Idle, main and power circuits all have some overlap.
Flathead man2
Senior Member
thanks guys 
I'm not so sure about the Edelbrock being "modern" Ron. It was introduced as the Carter AFB in 1957, later Federal-Mogul produced them and eventually Edelbrock bought the rights. Edelbrock had them built initially by Weber Carburetor, and today they are assembled by Magneti-Marelli for Edelbrock. I like the 390 Holley as a better choice for a typical street engine; the smaller venturi's will pull a stronger vacuum signal giving a better transition from idle to cruise and also have a snappier feel on the street than a 500cfm carb. Choosing between a Holley or Edelbrock is kinda like living in Chicago- Sox or Cubs? It all boils down to personal preference and experience.
Kahuna
Well-known member
Hi Trev;
I used the Teapots cuz they're cheap. No one wants them and they're of the era.
Hi Jim:
The Ken Austin deal is/was very unusual. When I first called him and asked about doing it, he said he probably could. We had several conversations over several months
and then nothing from him for almost a year, I think.
Then he called asking for an address to send me something. I gave it to him, asked him if he wanted any money (he said no) and again, nothing happened. A few months later a wooden box arrived with a manifold "mock-up" for me to check dimensions, make any changes and return. No changes were needed so I sent it back.
Maybe 2 months later the manifold arrived. On the underside of the manifold is marked
ADQ-1 (Austin dual quad #1). It is easily as good or better than anything I've ever owned. The casting is perfect, as is the machining.
Mr. Austin is a true gentleman in every sense of the word. I don't know how he's doing, as his site is down. I hope he is OK. I believe he's in his eightys. He'd been doing manifolds for over 50 years.
He also had another project that I was really interested in:
It consisted of making 24 stud aluminum heads with the water pumps cast into each head like the 21 stud engines. I could really fool alot of the "6 volt" guys then.
Regards to all,
Jim
Forgot to add:
The original agreed price for doing this was to be $ 500.00. When the manifold arrived, the bill included was $ 400.00. I called and and mentioned that we had agreed on 500.
He said no, that 400 was just fine and would not accept any more. Won't find many people like that.
I used the Teapots cuz they're cheap. No one wants them and they're of the era.
Hi Jim:
The Ken Austin deal is/was very unusual. When I first called him and asked about doing it, he said he probably could. We had several conversations over several months
and then nothing from him for almost a year, I think.
Then he called asking for an address to send me something. I gave it to him, asked him if he wanted any money (he said no) and again, nothing happened. A few months later a wooden box arrived with a manifold "mock-up" for me to check dimensions, make any changes and return. No changes were needed so I sent it back.
Maybe 2 months later the manifold arrived. On the underside of the manifold is marked
ADQ-1 (Austin dual quad #1). It is easily as good or better than anything I've ever owned. The casting is perfect, as is the machining.
Mr. Austin is a true gentleman in every sense of the word. I don't know how he's doing, as his site is down. I hope he is OK. I believe he's in his eightys. He'd been doing manifolds for over 50 years.
He also had another project that I was really interested in:
It consisted of making 24 stud aluminum heads with the water pumps cast into each head like the 21 stud engines. I could really fool alot of the "6 volt" guys then.
Regards to all,
Jim
Forgot to add:
The original agreed price for doing this was to be $ 500.00. When the manifold arrived, the bill included was $ 400.00. I called and and mentioned that we had agreed on 500.
He said no, that 400 was just fine and would not accept any more. Won't find many people like that.
Last edited:
Flathead man2
Senior Member
thank ya sir 
Ol' Ron
Well-known member
Yes I know they started out as Carters (1952 first year) and had many up grades along the way, Edelbrock included. Much easier to change rods. jets no so much. However the tuning kit makes it easier to find the right combination. We use an AF meter, with this it's easier to get the Power and cruse ratios in line with power and economy. Now with that said, you must follow this with changes in the distributor advanve curve. A lean mixture need more advance. Power is around 18/20 for WOT.
wga
Well-known member
Check out the WCFB. Flows in the 375 CFM range, and is ideally suited to a flat motor.
Barney Navarro, had his 4V intake made for this carb. They are easy to tune, smaller than a Holley. They were OEM on 50's Olds, Caddys, Pontiacs.
Some info from the Carb Shop website:
WCFB
The WCFB was Carter’s first attempt at a four-barrel carburetor. It was introduced in 1952. A total of 222 different WCFB models were made in the years 1952 through 1967. The WCFB was discontinued after the 1967 model year. I have seen a number of different meanings for the WCFB acronym. One employee of Carter once told me that it meant “wrought cast four barrel”; and used that terminology for years. However, a close friend who worked most of his life for Carter, chastised me for using this terminology. It seems the official Carter meaning was Will Carter Four Barrel (Will Carter of course being the inventor that started the Carter Carburetor Company). So I now use this designation when asked.
The WCFB is a “square-bore” carburetor; with three major castings: (A) throttle body (early aluminum, later cast iron); (B) bowl (zinc alloy) and (C) airhorn (aluminum).
I have been unable to find ANY Carter-published CFM ratings for any of the WCFB carburetors. However, for the purpose of argument, one may compare throttle bore size and actual venturi size of various WCFB carburetors to other models, which do have published ratings. WCFBs had approximate ratings from about 375 CFM to about 500 CFM.
The Carter WCFB was identified by a tag, which originally was placed under the drivers’ side rear airhorn-to-body screw. Various sources have attempted to positively identify WCFBs by casting numbers. This may be done in a few rare cases; but generally this is unsuccessful. While the various sources MAY be correct with their casting number tables, generally they are unaware that other carburetors may have used the same blank casting, machined in a different manner. Therefore, if one knows the carburetors identity, one would know what castings would be present; but the reverse is certainly not true. The reader should use any such tables with the proverbial “grain of salt”.
While some of the WCFB carburetors had no airvalve, most of the WCFB carburetors have the weighted airvalve to prevent the secondary from flowing until the engine demand was sufficient to require flow from the secondary. There were also a very few WCFB units that had vacuum controlled secondary. These units, like the vacuum controlled AFB carburetors, were (and still are) exceptionally troublesome. Carter discontinued this design after a couple of years.
While there are many categories of parts on the WCFB that look as if they should interchange; two in particular that give many enthusiasts problems are metering rods and floats. The metering rod is an extremely precision device. Most enthusiasts look only at the metering diameters; but do not realize that the LENGTH of the metering step is not the same for all rods. Carter utilized at least a dozen different step length profiles. When interchanging rods, unless one is deliberately changing the step length, one should compare the step length profile of the replacement to the original rod. The floats used in the WCFB are a double pontoon arrangement, connected by an arm. THERE ARE SEVERAL DIFFERENT FLOATS, WHICH APPEAR TO THE NOVICE AS IDENTICAL! Maximum buoyancy of a float occurs when the flat surface of the float arm is perpendicular to the fuel inlet needle. A method used by Carter (also Rochester in their 4G series, and Stromberg in most of their two barrel series) to adjust the fuel level was to move the height of the arm where the arm was soldered to the pontoons. Failure to observe this difference in floats may lead to carburetor flooding issues. Even if the float arm is bent to achieve the specified adjustment, the buoyancy
Barney Navarro, had his 4V intake made for this carb. They are easy to tune, smaller than a Holley. They were OEM on 50's Olds, Caddys, Pontiacs.
Some info from the Carb Shop website:
WCFB
The WCFB was Carter’s first attempt at a four-barrel carburetor. It was introduced in 1952. A total of 222 different WCFB models were made in the years 1952 through 1967. The WCFB was discontinued after the 1967 model year. I have seen a number of different meanings for the WCFB acronym. One employee of Carter once told me that it meant “wrought cast four barrel”; and used that terminology for years. However, a close friend who worked most of his life for Carter, chastised me for using this terminology. It seems the official Carter meaning was Will Carter Four Barrel (Will Carter of course being the inventor that started the Carter Carburetor Company). So I now use this designation when asked.
The WCFB is a “square-bore” carburetor; with three major castings: (A) throttle body (early aluminum, later cast iron); (B) bowl (zinc alloy) and (C) airhorn (aluminum).
I have been unable to find ANY Carter-published CFM ratings for any of the WCFB carburetors. However, for the purpose of argument, one may compare throttle bore size and actual venturi size of various WCFB carburetors to other models, which do have published ratings. WCFBs had approximate ratings from about 375 CFM to about 500 CFM.
The Carter WCFB was identified by a tag, which originally was placed under the drivers’ side rear airhorn-to-body screw. Various sources have attempted to positively identify WCFBs by casting numbers. This may be done in a few rare cases; but generally this is unsuccessful. While the various sources MAY be correct with their casting number tables, generally they are unaware that other carburetors may have used the same blank casting, machined in a different manner. Therefore, if one knows the carburetors identity, one would know what castings would be present; but the reverse is certainly not true. The reader should use any such tables with the proverbial “grain of salt”.
While some of the WCFB carburetors had no airvalve, most of the WCFB carburetors have the weighted airvalve to prevent the secondary from flowing until the engine demand was sufficient to require flow from the secondary. There were also a very few WCFB units that had vacuum controlled secondary. These units, like the vacuum controlled AFB carburetors, were (and still are) exceptionally troublesome. Carter discontinued this design after a couple of years.
While there are many categories of parts on the WCFB that look as if they should interchange; two in particular that give many enthusiasts problems are metering rods and floats. The metering rod is an extremely precision device. Most enthusiasts look only at the metering diameters; but do not realize that the LENGTH of the metering step is not the same for all rods. Carter utilized at least a dozen different step length profiles. When interchanging rods, unless one is deliberately changing the step length, one should compare the step length profile of the replacement to the original rod. The floats used in the WCFB are a double pontoon arrangement, connected by an arm. THERE ARE SEVERAL DIFFERENT FLOATS, WHICH APPEAR TO THE NOVICE AS IDENTICAL! Maximum buoyancy of a float occurs when the flat surface of the float arm is perpendicular to the fuel inlet needle. A method used by Carter (also Rochester in their 4G series, and Stromberg in most of their two barrel series) to adjust the fuel level was to move the height of the arm where the arm was soldered to the pontoons. Failure to observe this difference in floats may lead to carburetor flooding issues. Even if the float arm is bent to achieve the specified adjustment, the buoyancy
Flathead man2
Senior Member
That was kind of my question, cause if you look at the intake ports in the block and the manifold, you'd think how is this gonna work? Big carb for small engine. You'll burn up rings for sure. But the big question is how well do they run leaned out like that with a 4bbl?
51 MERC-CT
Well-known member
That was kind of my question, cause if you look at the intake ports in the block and the manifold, you'd think how is this gonna work? Big carb for small engine. You'll burn up rings for sure. But the big question is how well do they run leaned out like that with a 4bbl?
The 4bbl. 390 on mine runs on 2bbl's most of the time as do just about all others. So when when you are tuning it, for the most part you are really tuning a 2 bbl. carb.
Flathead man2
Senior Member
ok that makes since. he he
he he
Richard in Florida
Well-known member
Having changed jets several times I can tell you it's not that hard. All you to do is lift off the top of the carburetor with the carburetor still on the engine.
The jets are at the bottom of the bowls and easily changed. Replace the top and you're done.