Most of those adapters (inexpensive or otherwise) do not match up perfectly to the manifold throttle holes.  The factory ½” thick phenolic spacers for the Teapot manifolds had throttle bore holes larger than the intake holes so some mismatch in that area was normal even from the factory.  The Teapot manifolds are very flow restricted so doing some blending at manifold/adapter area will help.  For normal driving, that mismatch in the adapter to manifold holes will not be noticed.  But if really wanting to get the performance levels up, then you’ll need the ’57 and up ECZ-B manifold.

Lorena, Texas (South of Waco)

sorry to hijack thread but its relates to the OP's question. Ted, did the $15.00 speedway adapter fit similar to the pics I posted that show the size difference between the manifold ports and the adapter ports? I have yet to run the car with this adapter installed. Did you experience any flow issues? I can't help but think the restriction with sharp edges would cause some sort of performance issue? Thank You, Brett

1955 tbird 

Don't need an Adapter  when using the 57+ "B" Manifold with the later Carburetor. Just used 1/2 inch Phenolic Spacer to keep Heat transfer down.  

  

I find several carburetor adapters on the Speedway site that will work on the Teapot 4V intakes and allow the use of more modern flanged carbs.  As a FYI, the carb flange is the same on the 1954 thru 1956 4V intakes so carb pad interchangability between these manifolds is not a problem.
 
Here’s an adapter that’s listed for a flathead V8 and is by Edelbrock.  It’s on the pricey side being $70 but does provide some additional height.  Here’s the link.
http://www.speedwaymotors.com/Edelbrock-1106-Carburetor-Adapter-4-Barrel-Square-Bore-,108808.html 
 

The following adapter is the one I have used several of on dual quad intake conversions and gets the job done at roughly $15 each.
http://www.speedwaymotors.com/Universal-Carb-Adapter-Tapered-Port,69.html 
 

Lorena, Texas (South of Waco)

I have no idea how it lines up on an A manifold, The images i supplied are showing speedway adapter on an ECB manifold. Which one did you use for your B manifold?



1955 tbird 

How does it line up on a ECZ-A Manifold? I did mine using a B Manifold but I want to do my Buddys 56 using an adapter if possible before buying another B Manifold. Hard to find in Canada and shipping from US is mega expensive because of the Weight. 

  

depends on which 4barrel manifold your teapot came off of... 1955? If its the ECB manifold than you might have trouble finding one that fits. I will post pics of how the Speedway 135-1935B adapter fits on an ECB manifold. The manifold ports are smaller than the adapter  and looks like it could cause a flow problem.
 


1955 tbird 

Maybe 1351935B or 1351935 or 3251106


Lawrenceville, GA

Check Summit for Trans Dapt #2062 , I believe that's it and it's $33.97

Casco Thunderbirds sells them , part #9A589HB . Price is $79.95 which seems a bit steep . Probably get one through Summit Racing cheaper .