I am rebuilding a newly acquired carb for my 55. I am not sure if I will find a reasonably priced 57 distributor in the new future (I might opt for an aftermarket, but prefer original).   For now I will continue with the 55 distributor.

Question: If I modify the carb now and cap off the new vacuum port, with this create any problems while I'm still using the 55 distributor?

I don't understand your question. Why would you need to modify a 55 Teapot carburetor to use it with a 55 distributor?

Made a typo above (thank you for pointing that out) I am looking to use a 57 distributor to utilize centrifugal and more typical vacuum advance

Firstly, if you intend to use the Holley 4000 "Teapot" carburetor long-term, I would ask Sal Cicala to rebuild it. He could also modify it per Ted Eaton's article on eatonbalancing .com to be used with a 57-up distributor. If you fully intend to rebuild the carburetor yourself, I hope you know what you're doing (no offense intended). Modifying it to be compatible with a 57-up distributor, following Ted's instructions, seems simple enough. 

Going by the pictures in Ted's article, it looks like a more or less permanent modification, meaning that you need to be committed to using the '57 or newer distributor's style of vacuum advance and the carburetor will not work with the original distributor after modification.



Lawrenceville, GA

If you are keeping the 55 distributor, you need the carb in original 55 condition because you will need the original  type of  vacuum for the distributor  Without any .vacuum to the 55 distributor, it will not function properly most likely the result will be a poor running car. 


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Thank you for the suggestion and concern.  I asked the question because I don't understand the vacuum circuit of the carb.  I am not asking how to do it.  I am rebuilding a second carb so I will have one for each distributor (I already rebuilt the original carb and it's working fine) .  I thought if someone could answer my question it might save me time if I could just cap the "new" port and tune the second carb while I'm searching out a 57 distributor

On my truck with a '55 Teapot and '57 distributor, I simply run manifold vacuum to the advance with a pink butt splice stuck in the hose to delay the advance a little.  Has been working fine for about 10 years.

John - "The Hoosier Hurricane"

If using a ’57 and up mechanical/vacuum combination distributor in the Y, then here’s the link explaining how to modify the Holley 4000 (Teapot) 4V carbs so that those carbs can have an isolated ported vacuum signal.
Modifying the Holley Teapot four barrel carb for late model distributors – Eaton Balancing  

Lorena, Texas (South of Waco)

When I inherited my 55 Tbird, it had the original 55 Teapot carburetor and a 57 Tbird tach-drive distributor. It seemed to run okay as well, until I stepped on the accelerator; it would miss, and the Fordomatic would not downshift. Considering that the car had spent most of it's life inside the garage, I doubt that my dad knew that the carburetor and distributor weren't compatible. After reading Ted's article, I checked the carburetor to see if it had been modified to work with the 57 distributor; it hadn't. If you don't know what to look for, it's easy to mistake a 57 tach-drive distributor for a 55 tach-drive distributor. I didn't know what I had until I attempted to replace the 57 distributor cap with a new 55 cap; the 55 cap is smaller and won't fit a 57 distributor.