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By Sandbird - 8 Years Ago
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Being an owner for 40+ years of teapots I've never seen, or if I did I forgot, the CFM rating for the '56 or '57 E model teapots. Anyone happen to know what they are? The 57 E's have restrictors so they should flow at a lesser CFM than the '56 single 4 barrel teapot equipped engines. Just curious.
Thanks
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By NoShortcuts - 8 Years Ago
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Sandbird. The 1968 Edelbrock Catalog had a listing of Holley carburetors they were offering.
The E-Bird type Holley 4000s were listed as having an airflow of 330 cfm
Primary venturi diameter is listed as 1 1/16 inch
Secondary venturi diameter is listed as 1.0 inch
Primary throttle bore diameter is listed as 1 5/16 inch
Secondary throttle bore diameter is listed as 1 5/16 inch
Hope this helps! 
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By speedpro56 - 8 Years Ago
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Pony carbs rated the 4000 at 370 cfms and the lincoln at 390 cfms
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By NoShortcuts - 8 Years Ago
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Sandbird (11/25/2017)
Being an owner for 40+ years of teapots I've never seen, or if I did I forgot, the CFM rating for the '56 or '57 E model teapots. Anyone happen to know what they are? The 57 E's have restrictors so they should flow at a lesser CFM than the '56 single 4 barrel teapot equipped engines. Just curious. Thanks
Sandbird. Yes, the primary venturi booster clusters have 'donuts' (brass 'washers') secured on the bottom of each booster opening. The securing was accomplished by using a doming tool (jeweler's tool) or the ball end of small ounce ball pein hammer to enlarge the bottom opening diameter of the venturi booster opening so the donut does not fall off. Don't laugh! That's all that held them in place! 
Over time, several Forum members have suggested that the washers served as restrictions to air flow to improve low speed engine performance by eliminating flat spots.
I theorize that the washers were used to alter the flow of SOME incoming air by redirecting it as it headed toward the venturi directly above each primary throttle plate bore. Unlike the primary throttle plate venturi boosters that serve to concentrate the air and direct it toward the center of each primary venturi, the booster venturi brass washers served to disperse some air causing it to be drawn-in more toward the perimeter of each primary venturi opening.
I speculate that this was done to reduce low speed engine bog when accelerating from a low engine speed and to improve engine low speed part throttle throttle response.
While the optional '56 Power Pack and '57 E code carburetor primary venturi booster brass donuts (brass washers) may somewhat obstruct air flow into the primary venturis, I suspect that making some air tumble into each primary venturi above the primary throttle plate had more to do with homogenizing the air fuel mixture to improve low speed performance. Personally, I'm doubting that Holley 4000 carburetor cfm air flow was measure-ably reduced by the addition of the venturi booster washers.
This is all Charlie Brown thinking and I've never heard anyone else suggest it.
I've had one very knowledgeable and resourceful y-block acquaintance suggest that in his experimenting with Holley 4000 2x4 set-up nuances, he found that increasing the O.D. diameter of the brass donuts improved engine low speed performance and throttle response. Talk to Jerry Ponder in Alabama about Holley 4000s for 2x4 or supercharger set-ups for all kinds of information you may never have heard before.
Hope this helps!
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By Sandbird - 8 Years Ago
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It looks like my question has been answered.
Thanks guys.
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By Ted - 8 Years Ago
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I’ve been led to believe that the Lincoln Teapot carbs were in the 490-500 cfm range. 330 cfm for the restricted venturi dual quad Teapots sounds reasonable and especially when they are used in pairs.
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By Pete 55Tbird - 8 Years Ago
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When you talk about carburetor CFM rating I find it interesting to note that the CFM of a 2BBL carb and that of a 4BBL carb are not a linear value.
A 500 CFM two-barrel does not flow the same amount of air as a 500cfm 4-barrel. It's easier to quote than to explain: "The cubic free per minute, CFM, rating for 2 BBL and 4 BBL carburetors can not be directly compared. 2 BBL carburetors (and 1 BBLs) are tested with a 3 inch vacuum while 4 BBLS are tested with a 1.5 inch vacuum. In other words the CFM tests for 1 and 2 BBL carburetors are done with the testing equipment sucking twice as hard. If you want to compare the CFM rating of a 2 BBL to that of a 4 BBL multiply the 2 BBL rating by 0.707. ". Grassroots Motorsport
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By NoShortcuts - 8 Years Ago
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Pete 55TBird. Hmmmm... I'd forgotten that info, Pete. Thanks!
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By pegleg - 8 Years Ago
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Ted, sounds about right. The MPH of the red car is exactly the same with my 500 Edelbrock or the Lincoln teapot. Of course that assumes the carb is the limit on air flow and not the intake or the heads.
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