OK, Thanks. I have a few more of these carbs around, I'll look at what is in them. I have had a hard time finding venturies so if it turns out they are not too expensive I may get some of each size to play with once the engine and car are ready. It's not tough to change them and it's easy to make them bigger if need be the carb body being the limiting factor. These carbs were used on GMC trucks with 228 and 248 engines and on Internationals with 261s. I'll have to look at their flow rating.
