I find it hard to believe that there is only 50 cfm difference with 1/8 inch difference in the primaries. I will acknowledge that it is "referred to" as an 800 but I am actually talking about actual flow.
I suppose you are best to argue your points with the experts , as that's what I use for reference http://www.thermoquads.com/, and he has a reaally, reaally good reputation. Ask him, he is a member here, and I'm sure he will gladly give you a straight up answer. Who knows the carb. probably only flows 775cfm. Fact of the matter is, it is rated @ 800cfm.
My 340 is starving for fuel with a 750cfm rated Eddy card.
Nonetheless, your throttle response has little to do with cfm, aside from working in sink with your timing/vacuum advance.
Your spark timing and advance curve is the key to your throttle "response".
