[Roar]

Multiple carbs and flow. Ok as you said if you add all you carbs flow # together you will get 1250 cfm. But it just dosnt work that way. With multiple carbs the engine sees em as one. So the real flow will be less. So the 800 cfm is more accurate.
For example. a 455 will usually take a single 850 cfm carb good and run strong. Ok now you decide to go with 2 carbs. And you will find out that 2 600 cfm carbs will work great and the engine will run nearly the same. but hey this dosnt add up I now got a 1200 cfm carb if we calculated like you did in the beginning. But in the real world the engine will see em as a single 850 cfm carb.