Yes, the reason is more power. But how does it make more power? Well, its not the delivery of more fuel, that would cause the engine to run rich and that would be bad. This is the gist of it. This allows the engine to breath better. It all has to do with these things called venturis, where the fuel and air mix and the amount of air flow. Try only breathing through a straw only while running or exercising. You'll notice it is rather difficult to keep up with the air your body needs. Same principle applies to an engine. By letting more air flow easily, you will have more performance. This is also why people put 4 barrel intakes on V8s and yank off the 2 or 1 barrels. The engine gets all choked up.
This is a very simplified explanation. There are a bunch more factors and such that I know a little about from working with my hit and miss engines. It is all very complex.
One other thing I noticed too is, it starts much better too. It started great before, but it is even better now! Usually when it is cold, I'll have to choke it and leave it half choked with the throttle on a bit until it warms up. However with the two carbs, I choke it all the way and it fires right up as soon as I turn the key and I can turn the chokes off all the way and it will stay running. �:o Then when it is warm, I can turn the key and it will fire up right away. Just the way I like engines to start. �8-)
