There are a couple of different versions of the Carter BB1. The most desirable is the all cast iron version which does have an adjustable GAV valve. The other version is a cast iron top with a pot metal, or aluminum base. Some of these have an adjustable GAV, some do not. All have an accelerator pump. While all of these basically have the same throat diameter and mounting flange, the venturi size can vary quite a bit depending on what its original application was. I don't have one in front of me, but the mounting flange looks like a stock Model A, but it is definitely bigger as is the throat diameter. I guess to use one on a stock Model A manifold you would need a reducer flange. The throttle shafts are typically made so they can be used with a universal adapter and have a flexible throttle arm position. They are good carburetors and are often fitted to early brass era cars as a more reliable option to the rare and often difficult early carburetors. I have also seen some of the Model T guys use these on Ts-especially with overhead valve conversions. I don't think I have seen one fitted to a Model A but that doesn't mean you couldn't. Parts for these BB1s are readily available and there are a couple of carburetor shops that rebuild them, but, there is no reason you could not rebuild one yourself if you find a good core as they are pretty straight forward.
