A engine will only pull in as much air and fuel as it needs. If the carb is to small for the required engine demand, then a bigger one will work better. Any modification to said engine, should require more fuel and air, thus producing more power, so yes a bigger carb will make more power, but not by itself.
Most of what you read is a sales pitch. Use some of the online calculators when figuring carburetor size and be realistic on the rpm range you are going to use the engine in, and you will find it won't be very big.
Here are some calculators for you to mess, with,
http://www.wallaceracing.com/Calculators.htmJoe
