all carbs would behave the same....the more fuel it can deliver then the faster it should go (but not necessarily efficient)....however, the catch is....TUNE UP ba? Tama ba ang air/fuel mix.

I would suggest look at both carb brands that you plan to get and see which ones are easier to 'MANIPULATE' for the settings of the carb - to make it lean or rich.....meron iba (like stock carbs) na good enough na but some are so complicated....

the Weber 40 .... isn't that the dual carb (aka twin-side)?...mostly for 4cylinder cars yun kasi dalawang carb ito na kambal ang mechanical movement. It gives more air (and fuel) to the cylinders.

It is like giving each of your cylinder a carb of its own and tuning these different carbs para sabay and equal ang buga ng fuel to each of the cylinders.....

my 2 cents.