I get it.  I've been down the rabbit holes at Mummert / Eaton, etc., for about a decade now.   I would likely sell the Teapot and go with a 4bbl and a 57 street cam.   I had a 57 Ranchero that I intended to build but I sold it, unfortunately, since my spouse didn't like it.   But she's on board with a Thunderbird.   And I kept the wheels and tires from the Ranchero.   Buyer didn't want them.   But they will fit the Thunderbird just fine!

Assuming you have the original axle ratio, I would ask John Mummert what he thinks about using his 280-11 cam, if you will use his aluminum heads. I'm sure Ted could recommend something as well. If you haven't already done so, read Ted Eaton's "Unported Iron Heads Can Still Make Over A HP To The Cubic Inch." The Isky cam selected for that build was larger than what you're considering, even though Karol Miller's Victoria had 3.22 rear gears/w overdrive transmission.  

I'm not sure what the rear end ratio is in the 56 Tbird yet.  It was originally delivered as a 292 three speed manual so it should have a 3:73.   The prior owner later pulled that and put in a rebuilt 312 with overdrive.  And yes, I did read the article about 1 hp per cubic inch in a 292 at Ted's site.    I like his approach, he does no more than necessary but does it the right way.   The Karol Miller build was very interesting.    This was my adventure today, pulling a 272 Marine Y-block from a derelict 1960s Higgins speedboat.  It has ECZ-G heads and Glenwood aluminum marine exhaust manifolds.   Engine is normal rotation, not seized and maybe low hours being a boat.  Total cost $125 but I burned about 12 hours of my time.   It will be interesting to tear into it.  

Will a stock Ford distributor cap fit on a CRT distributor?

The CRT/TSP electronic distributors with the tach drive are an option if determined to go with a mechanical tach.  Those are reasonably priced and I will use them even on non-mechanical tach applications.  Those distributors are available in both the HEI terminal and push-in-wire caps depending upon your preference.

Lorena, Texas (South of Waco)

No.  But both the HEI and push-in wire distributor caps are available for the CRT/TSP distributors.

Lorena, Texas (South of Waco)

Here are a couple of pictures of a CRT/TSP distributor in a Y. Keep in mind that the tach drive distributor is taller overall than the non-tach drive distributor.  The distributor caps are available in black, red, or blue.
  

  

Lorena, Texas (South of Waco)

My 56 T-Bird arrived and I finally had a chance to give it a good look over.   Prior owner had changed the original 292 to a rebuilt 312 (225 HP) engine from a donor car.   CR is 9.0 to 1.   Heads are ECZ-G which was a pleasant surprise.   I assume the cam is 57 spec but have no way to confirm.   The intake, carb and distributor, however, are all 56 spec (teapot, etc).    Transmission is the T85 Heavy Duty unit with OD.    Rear end ratio is 3.92 per tag (47/12).    I’m thinking this will be a real strong performer with my Blue Thunder intake, CRT/TSP tach drive distributor and the right 4 bbl carburetor.   I have a stock 57 Holley (1273 list) but I’m wondering if that will be enough with the Blue Thunder intake and new distributor.   Thoughts?

If the camshaft in your engine is the OEM 56, or even 57 cam, the 57 carburetor will suffice. The cam will limit the upper rpm range, so a larger carburetor will not be necessary. Even if you were to modify the Teapot to be compatible with the 57-up distributor, the 57 4150 carburetor provides a bit more cfm and would be preferable. However, I don't think the 55/56 air cleaner for the Teapot will fit the 57 carburetor. 

The Blue Thunder intake manifold is expensive. If you have the stock cam and either the Teapot or 57 carburetor, I don't think there is much to be gained by using the Blue Thunder; the 57 ECZ-B intake would be considerably cheaper and work just fine with your combination. 

Even with the 69cc ECZ-G heads, your static compression could be less than 9:1, particularly so if neither the block nor heads have been cut, you have composite head gaskets, and aftermarket cast pistons that could be as much as .035 below the deck at TDC.

If the engine runs fine, as is, I would do nothing more than go with the electronic distributor, 57 ECZ-B intake and carburetor, and possibly the 57 exhaust manifolds. 

You might verify whether you have the 56 1.43 ratio rocker arms or the 57 1.54 ratio, the latter should be preferable, even with the 56 camshaft.