Other than the carburetor mounting flange, are the intake runners different?  Does the "B" flow more just because a larger carb can fit on it?  

Yes, it's a better flowing manifold; it's Ford's best single 4-barrel intake manifold for the Y-block. If you want more flow, open up the carburetor base to two ovals and blend where the runners enter the plenum. If you want more, buy Mummert's aluminum intake or a Blue Thunder. 

55blacktie, 
What would be the preferred direction to open a B manifold to the two ovals you speak of, side to side or front to back? 

JDC

Deyomatic, check your PM.

'55blacktie...Thanks for the info.  I'll look into that.  For whatever reason, the site won't let me reply back to you.  
That would save me from finding a local machinist...and, if he's willing, I know it would get done right.

Thanks again.

Deyomatic, you're welcome. I sent another PM. 

If you don't already have a 57 ECZ-B Intake manifold, you might want to buy Mummert's aluminum intake. However, keep in mind that it doesn't have the heat crossover for the heat-riser choke found on the original 57 carburetor. If originality isn't important, and you have a carburetor with electric or manual choke, the lack of the heat crossover won't be an issue. I have an electric choke, and I will completely block off the crossover. It's common for the paint to burn off on the crossover, and it can contribute to fuel problems, if a phenolic carburetor spacer isn't used. 

55- it is really weird that I can't send you a PM.  Feel free to PM me your email address if want...
I DO have an ECZ-B already in use...I was thinking of picking up another so I could take my time and port it then just swap it on in a day or so and not miss out on any cruising time.  I had the thought that maybe the "A" manifold only needed opening up up top and that I could save some coin and port that, turn a spacer into an adapter and not miss out on cruising.  Sounds like any machine work on this "B" manifold will have to happen over the winter...and this is in a 1930 Model A...originality has never been a concern!

Deyomatic, I just read one of your older posts. If you have ECZ-G heads, I don't think I would bother porting the earlier Teapot intake; go with the ECZ-B or Mummert. 

Blue Thunder also has a YBlock aluminum manifold available. It has the exhaust heat crossover which does help with atomization and street use it you live in a cooler climate in winter. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.