umm sometimes more flow doesnt always make more power...dyno charts are good for verifying this but many v8 engine builders who get better flow numbers on the bench, make less on the dyno - two words: tumble and swirl...very important in atomization and evaporation of fuel because believe it or not it takes a lot of energy to do that. I know a guy who works in a fuel injector lab (ill not say the company so as to cover my ***) and they have a flow lab right across the hall with about a $200k flow bench for just such measurements - tumble being the circulation of air perpendicular to the cylinder axis and swirl being circulation about the cylinder axis. Hondas technology in their combustion chamber, piston, valve, timing and port design for this is absolutely astounding and allows them to burn very very lean mixtures and although it was aimed for better emissions I am sure they will use it to gain more power in the future....as far as you are concerned the throttle bore will dictate the air velocity at any particular flow rate which is dependent on rpm but you should get less parasitic pressure drop with the larger bore - go with the dyno but be weary as to what else was done to the car before it was dynoed - different numbers may have alot to do with what is going on in the head and most ppl arent willing to share their flow bench magic...

 

I entirely agree for a so-called "wet" (carb) manifold where fuel and air are flowing and swirling and mixing and atomizing and evaporating in the manifold, however these are "dry" manifolds with direct port injection. There is only air flowing thru them. No fuel until the actual intake port of the head so no fuel to atomize or swirl or mix ...strictly airflow alone. Your described technique is just the thing for porting heads but no longer accurate for the dry manifold where there is no air fuel mixture flowing.. Thus the process and results are different from ye olde fashioned intake manifold porting and polishing with Carbs where fuel and air were atomizing and mixing and flowing together.