So I've been looking around for a 400 CFM AFB to add to the upcoming build of the 261 and I've realized they are kind of hard to find. A friend of mine has an AFB laying around off a Buick but the model number doesn't have a CFM rating. After doing some digging, I came up with this, its a 4331s Buick carb info the info that I can find about the 9400 AFB says the throttle bores and the primary and secondary Venturi are the same size as the 4331s. Would it be a safe assumption that this carb flows at about 400 CFM? Its for a 340 V8 but only 400 CFM seems a little anemic to me for that displacement.