This may be part of the answer from Hemmings
When Carter began producing its BB-1 carburetor for use in 1932 Chrysler products, it didn’t take technicians of the Thirties long to realize how much more advanced it was than any offerings from Zenith, Stromberg and other updraft carburetors of the same era. The carburetor often appeared on any other manifold it could fit, and Carter soon took advantage of its popularity and began marketing replacement bolt-on carburetors to retrofit onto cars, trucks, tractors and inboard boat engines. The Carter BB-1 is still an often sought-after unit for many classic car enthusiasts, and several iterations of the Ball & Ball updraft are still found at swap meets and pick-a-part yards today, if you know where to look. BB-1 carburetors (and the newer BBR-1s and BBR-2s) were used on many production cars:
The Carter BBs were also used in thousands of industrial and/or farm applications using six-cylinder Chrysler engines.
Like most early Carters, BB units can be identified by the aluminum tag mounted on one corner of the fuel bowl, usually a three-digit or four-digit number followed by an “S.” A second letter after the “S” indicates an engineering change from the original part number. Identification without that tag is extremely difficult; however, The Carburetor Shop does offer a carburetor ID service for $10, if you send them the carburetor.
Three different BB units were offered, and they are usually referred to by their size designation, established by SAE. Size one units have a one-inch bore and a 23⁄8-inch mounting pattern for the intake manifold. Size 2 carburetors have a 1¼-inch bore size and a 211⁄16-inch mounting base; and Size 3 units have a 1½-inch bore size with 215⁄16-inch manifold bolt pattern. Ball & Ball units are desirable because of their slender body, which fits in tight engine locations much more easily than other updrafts. The BB’s main metering jets are easily adjustable from outside the carburetor body, and they have an adjustable idle circuit as well. The throttle shafts are long and have a universal clamp-type throttle lever, making them easily adaptable to various accelerator configurations.
When sourcing a good Carter Ball & Ball, try to find one that came off an automotive engine; many units were designed for use on trucks and boats and are not as easy to adapt for passenger cars. Marine units have different accelerator pumps, and many truck units were equipped with vacuum-type governors. These units can be altered, but it is more expensive.
Replacement carburetor kits are still very easy to locate, and some replacement items used to adapt truck or marine units to passenger cars are available but expensive. It is also important to note that Carter B&B carburetors do not like having the accelerator mashed repeatedly; they are designed to start by one primer tap on the pedal, and then use of the choke is all that is necessary. More Carter updraft information is available at The Carburetor Shop’s website and a detailed repair procedure brochure is available online at The Old Car Manual Project, www.oldcarmanual.com.
The Carburetor Shop 573-392-7278www.thecarburetorshop.com