I am running a Holley teapot carb on a 56 victoria that I am tinkering with. It is currently just a yard driver. I noticed a gas leak at the rear of the carb and traced it to the large brass screw, the fuel inlet plug at the rear of the main body. I tried to tighten the screw and found that the threads  were stripped . as a temporary fix, I took out the screw and eliminated the gasket and smeared a bit of JB weld on the threads of the brass plug. Eliminating the gasket allowed the plug to catch on some of the deeper threads and it tightened enough to seal and not leak. Good enough for a yard driver for now, but I will need a new main body should I decide to rebuild this carb. I have an extra core from a 55 teapot but not a 56. I have observed that the main body top cover is obviously different when comparing the 55 to 56 teapots and the brass tubes feeding into the top covers are different. However, the main bodies on 55 and 56 models appear identical. I also remember that the 56 models have discharge nozzles and the 55's don't. I remember because I broke the beak off of one of those nozzles trying to pry it out years ago. I hope someone on here might know if the main bodies on these two years are interchangeable.  Thanks

Seems ;
The Idle air bleed could be different size
Accelerator pump bore different size
Main Jet but that is easily swapped out
Needle and seat is threaded in and others held in by an extra spring
The "discharge nozzles" also have a cutaway on the back that go part way on early or all the way, there are three designs! so far as I can tell. (There is also a small air bleed that might be different size)

The differences might not make a lot of difference in an occasional driver.
Look at the inside bottom for a cast in part number. They might be the same. If so you could swap top cover and secondary tubes.


1936 Ford 3W Coupe : 56 T-Bird 312, 47 Packard 3 speed, 40 juice brakes.
1968 Merc Cyclone FB GT 390, Getting a better front clip!
1977 Ford F-250 Supercab RWD Explorer Long box.
1976 Chev Camaro RS LT
Future rebuild : 1949 Ford F-1