I had to install three washers under each bolt that holds the stand on the intake manifold to raise it enough to make the stock linkage work.  I also had to extend the turnbuckles almost their entire length.  The accelerator pedal arm had to be tweaked a bit, but it all came together and works decently.  My accelerator pedal rod has been welded at least three times in the past, so it may be part of the problem getting everything to fit together well.  A 3"x14" K & N filter assembly with the drop down base will work with a 4150 style Holley carb where the fuel lines drop down and not to the top side of the bowl.  I installed one of my 735 CJ carbs on the engine just to see if it would work.   Joe-JDC

JDC

Oops. My error.  Photo shadows & perspective distortion rather deceptive.  Closer inspection demonstrates Phil still has (essentially) the orig. ‘55 linkage.  Parts on both setups seem juggled a bit from stock though.
Studying the ‘55/‘56 throttle assemblies DOES make me curious about one thing:  The bellcrank/linkage-articulating part (7A185) that bolts to the intake manifold has two ears (with bolt holes) that stick up.  Yet, I can’t find any indication there was ever anything to be attached there (?). Puzzling. 

6 VOLTS/POS. GRD. NW INDIANA

I’m curious:  Joe has retained the ‘55-style two part OD shock absorber throttle rod assembly, but Phil has the ‘57-style single rod.  I’m wondering why they changed the design when they went to the larger Holley carb in ‘57 (?).  If both designs work equally well with the later carb, it must have been a cost saving issue, unless Joe’s carb is somehow better suited to the earlier linkage (?).

6 VOLTS/POS. GRD. NW INDIANA

I can see where using a drop-base air cleaner could have a clearance issue with the Edelbrock carburetor fuel inlet, but I don't see a difference between the dual-feed inlets of my Holley 4150 Street Avenger carburetor and the dual-feed Summit carbs. When I test-fit the Summit air cleaner on my Holley carb, I did not observe any clearance issues. I have yet to install the carb and air cleaner on my car, so I will check for clearance issues again.  

Installed Holley dual-feed hard lines on the Street Avenger carburetor and installed the base of Summit G3000 air cleaner. No clearance issues. 

If you look up SUM-G3000 on Summit's website, you'll find that it is stated in the description that Edelbrock and Carter-style carburetors require a spacer. There's no mention of the Summit carburetors requiring same. 

The 14" drop base air cleaner will only work with Holley style carbs.  It doesn't work with the Summit or Edelbrock carbs where the fuel line is off the top side of the carb.  Joe-JDC

JDC

In Joe's and Phil's photos, the air cleaners are smaller in diameter than an OEM Tbird/Ford air cleaner and considerably smaller than a 14" round/oval air cleaner. As far as hood clearance on 55-57 Tbirds is concerned, that needs to be taken into consideration. A Summit 14-inch round air cleaner/w drop base and 3" element will allow enough hood clearance for a 1/2-inch carb spacer. On the other hand, my Billet Specialties 15 x 8 1/2 x 3 oval air cleaner, which does not have a drop base, will barely allow the hood to close/w no carb spacer. 

According to ford-y-block.com, the Mummert Tbird intake manifold is 0.180-inch taller than stock.

If you have a modern Holley carburetor, the PCV hose can be attached to the carburetor, no need for the Casco spacer.

On the 2019 EMC 303 Y, with iron heads that flowed ~245 cfm, we made 437 hp with the ported ECZ-9425-B iron intake shown in the picture.  Not bad for a little Y.  The fully ported Mummert made 454 hp, and with the new SP the same engine made 463 hp.  All that with 10.4 compression ratio.  Joe-JDC

JDC

By milling the carb pad down like the picture above, it allows you to use a phenolic spacer to keep the carb cooler and run a PCV if you so desire.  The 1" spacer with the PCV fitting is available from CASCO or Larry's Thunderbird.  If you are willing to use a different air cleaner on the Thunderbird, you can install a 1" spacer without hitting the hood.  Joe-JDC

JDC

The "B" manifold fits fine in my 1955 TBird.  I also have a 1/2" PCV spacer under my Holley carb. The stock TBird air cleaner will work also.  I use a custom air cleaner.   According to the Mummert website, he sells an shorter aluminum intake for TBirds.

Wanna trade? Just kidding, but I do intend to have mine done. Years ago, my machinist friend opened up the plenum of my 289 manifold, and I gasket-matched the runners. Hopefully, paying to have my Y intake done will be cheaper than Mummert's aluminum intake; otherwise, I'll sell mine and buy Mummert's. My only concern is limited hood clearance on my 55 Tbird. According to John's description, his Tbird intake is still a bit taller than my 57 intake. A dropped air cleaner  is necessary when using a carb spacer.