I think some will just never get it when it comes to carb cfm.......
There was a YT video of a bloke putting a lawn mower carb on a 289 Ford.....& getting quite good acceleration.
The engine takes the cfm it wants from the carb. Put a 750 carb on a 340; it might use the 750 cfm IF it is a high output engine that revs to close to 7000 rpm...with a 100% VE. Less VE, less air ingested.
A good way to see this in action is to see an engine on the dyno with an air valve sec carb like an AVS or TQ. And an overhead camera. A big engine will pull the AV open at lower rpms than a smaller cube engine.
The risk of putting big carbs on an engine that will not use the cfm is that it hurts low rpm throttle response. If one size fits all, then that would be what we have....but we don't. You also need to factor in the atomisation/distribution quality of the carb.
David Vizard made 460 hp on a SBC with 48 IDA Webers, one carb bore [ 48 mm ] per cyl, 320 cfm. An 850 Holley on the same engine was down on power everywhere, made 435 hp.
