Which carb?

[Rigley]

In response to suggestions on a 4bbl for my flathead several members suggested a early GM carb. The problem I have is when going to swap meets is the sellers do not know what the carb was on. My question is how to recognize a suitable carb?

[JeffB2]

You could use this:http://www.summitracing.com/parts/trd-2064/overview/ this will adapt your small base intake so you can use a more modern 4 barrel like a 390 CFM Holley which you can easily find parts for.Using a Carb that has been out of production for over 50 years would be a real crap shoot to find one that is not worn out and will be hard to find replacement parts for.

[Motorhead6]

Take a gasket that fits on the intake carb surface with you to the swap meets and use this to assure that you get a carb that will bolt on. As an alternative, make a cardboard pattern to take with you. Any of the early carbs will work fine as all early engines were of relatively small CID; as long as the bolt pattern is correct. Keep in mind that you need a WCFB. If you need a picture, go to e-bay and print one of the myriads ones on there for sale. Mostly early GM V8 engines is where they were used.

Someone may jump in here and object that some Cadilacs were a little larger etc., but they are not so much bigger that you won't be able to just re-jet the carb to work just fine. The later, larger engines used larger CFM carbs and that is why they went to the larger bolt pattern carb bases. So stay with the small bolt pattern carb and you will be just fine.

[frank long island]

I agree with jeff why use something old and worn out when you could use a modern easy to get parts for carb just my thoughts

[scicala]

Originally Posted by Rigley

In response to suggestions on a 4bbl for my flathead several members suggested a early GM carb. The problem I have is when going to swap meets is the sellers do not know what the carb was on. My question is how to recognize a suitable carb?

I know I mentioned it before, but if you want a Holley teapot carb, I have some. If you're flathead has a loadomatic style distributor, Teapots have the correct vacuum signal for that.

[Fordors]

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This may help- you will find some pictures and also descriptions if you read through them.

http://www.fordbarn.com/forum/search...archid=3598509

As a car guy I always liked the challenge of taking something old and making it look good and function well again. Look for a carb that is complete, you can always take off the automatic choke for instance and make it manual. Floats, gaskets, etc. are around for just about anything.

I can't get link to work; I just did an "Advanced search" for WCFB on the Early V8 Forum.

[Dick's Hot Rod Place]

Fellows, just a heads up.....there are just as many and as easily accessable parts and pieces for Holley 94's,, Rochester 2G's, and Stromberg 97's as there are for late model carbs and a bunch cheaper. If you want only new stuff, why are playing with old automobiles?

[scicala]

Originally Posted by Rigley

In response to suggestions on a 4bbl for my flathead several members suggested a early GM carb. The problem I have is when going to swap meets is the sellers do not know what the carb was on. My question is how to recognize a suitable carb?

When looking for a carb, Carter WCFB's and Rochester 4 GC's are hard to identify if they do not have the part number tag under on of the screws still on the carb. Otherwise they are hard to identify unless the seller can verify it for sure, or you know carbs very well. Holley teapots were always stamped with the carb part number and date code on the actual carburetor. Not on a removable tag.

Here is a website that will help you identify any American carb by the part number.

http://www.thecarburetorshop.com/Passengerkits.htm

[JeffB2]

Originally Posted by scicala

I know I mentioned it before, but if you want a Holley teapot carb, I have some. If you're flathead has a loadomatic style distributor, Teapots have the correct vacuum signal for that.

We know that you can do a class A rebuild on these Teapots which would be a good bolt-on and about the correct size for a flathead,since most flathead cars had a manual choke can you set them up that way?

[scicala]

Originally Posted by JeffB2

We know that you can do a class A rebuild on these Teapots which would be a good bolt-on and about the correct size for a flathead,since most flathead cars had a manual choke can you set them up that way?

I haven't set up a teapot with a manual choke before, but it is possible. I would recommend using a 1953 thru 1955 style teapot for this since they didn't have the auto choke mounted on the carb itself (was mounted to the side of the manifold below the carb).
You would probably have to fabricate an extension to the choke lever on the carb, other wise the throw of the lever might be too short and would be very sensitive to find the right choke position for a cold start. Then would have to fabricate a bracket to hold the choke cable and attach it to the carb somehow.
Or you could use a 1956 style teapot with an auto choke mounted to the carb as it came originally. Then replace the black choke cap with an electrically heated cap and wire to a 12 volt source when the ignition is on only. Could also run a hot air tube to the exh. manifold for that type of heat to the choke insytad of the electric choke cap.

A 1954 Mercury had the smallest flow teapot made for cars and was on a 256 cubic inch Y-Block. Would be the closest to the flathead's displacement.

[scicala]

Originally Posted by Motorhead6

Take a gasket that fits on the intake carb surface with you to the swap meets and use this to assure that you get a carb that will bolt on. As an alternative, make a cardboard pattern to take with you. Any of the early carbs will work fine as all early engines were of relatively small CID; as long as the bolt pattern is correct. Keep in mind that you need a WCFB. If you need a picture, go to e-bay and print one of the myriads ones on there for sale. Mostly early GM V8 engines is where they were used.

Someone may jump in here and object that some Cadilacs were a little larger etc., but they are not so much bigger that you won't be able to just re-jet the carb to work just fine. The later, larger engines used larger CFM carbs and that is why they went to the larger bolt pattern carb bases. So stay with the small bolt pattern carb and you will be just fine.

Two things I don't understand are, why does he have to use a WCFB and not a Rochester, a WCFB or a Holley teapot, or for that matter a Stromberg 4 bbl.

Also, how does re-jetting an over sized carburetor make it flow less air ?

[Motorhead6]

Originally Posted by scicala

Two things I don't understand are, why does he have to use a WCFB and not a Rochester, a WCFB or a Holley teapot, or for that matter a Stromberg 4 bbl.

Also, how does re-jetting an over sized carburetor make it flow less air ?

He doesn't have to, but his question was relative to early GM carbs and WCFB is the best choice there. I have a teapot on my flathead and it works and looks great. I recently rebuilt an early WCFB for a friend for use on his flathead; that also is a great choice. Late model carbs will also give great results if that is how one wants to go. Who are we to tell him what to use?

Re-jetting a carb will, of course, not make it flow less air on a given size engine as you well know. However, if one uses the same carb on different engines, at different atmospheric conditions, or with different camshafts or other equipment, it is necessary to check the jetting to assure proper fuel mixtures.

[scicala]

Originally Posted by Motorhead6

He doesn't have to, but his question was relative to early GM carbs and WCFB is the best choice there. I have a teapot on my flathead and it works and looks great. I recently rebuilt an early WCFB for a friend for use on his flathead; that also is a great choice. Late model carbs will also give great results if that is how one wants to go. Who are we to tell him what to use?

Re-jetting a carb will, of course, not make it flow less air on a given size engine as you well know. However, if one uses the same carb on different engines, at different atmospheric conditions, or with different camshafts or other equipment, it is necessary to check the jetting to assure proper fuel mixtures.

Rigley's original and only post said that other members suggested using an early GM 4 bbl. We are giving suggestions because his title says "which carb". As far as jetting and air flow goes, we both seem to understand that.

I agree that a slightly oversized carb (airflow) my need to be re-jetted for a more optimum fuel mixture (not always), but also is not best for throttle response at low speeds. I'm not down grading WCFB's, but just trying to state what is available.

[Ricks Garage]

Something like this would be different, 2 Holley 94's on a 2x2 adapter on 4 barrel adapter. 4 Barrel adapter is drilled for different patterns. This went on a 289.

[scicala]

Originally Posted by Ricks Garage

Something like this would be different, 2 Holley 94's on a 2x2 adapter on 4 barrel adapter. 4 Barrel adapter is drilled for different patterns. This went on a 289.

Not a bad idea Ricks Garage. Also less expensive carbs and very easy to work on. Would be the same as having a 4 bbl. with mechanical secondaries, or open them at the same time, plus they came in different air flow sizes to make the flow you need (94's 1" and 1 1/16" venturi').