Another Carb Size Question

Bob, the thing about carbs is that if you take the time to tune them, you'll find that any carb on top can be dialed in and run. A properly sized carb will not lack in low end response or give up top end HP. And this is where you can confused with how people do things and what magazine dyno's report. In general, on line calc's are slightly small in there cfm rating.

The on line calc you got for 647 cfm is closer to what you could use and have built dispite the fact it isn't a race engine.

Considering your build, I would not think twice or second guess myself on a 650 cfm carb.