Mike & Kevin, thanks for your replies. I probably should have been a bit more specific in my question/post. I previously had a Holley 1940 carb on my 66' - 200ci engine (currently I have an Autolite 1100), but I am not sure whether there are two different 1940 carbs, one for the 240ci engine and another for the 200ci engine, or are they the same?? You mention that you think there are two different throat diameters; could one of them be for a 240ci and one for the 200ci??? Thanks, Jim