Here are a couple of articles:

http://www.thecarburetorshop.com/Dual1barrelcarbs.htm

http://www.thecarburetorshop.com/Triple1barrels.htm

Most enthusiasts today go for multiple carburetors because of looks. As one earlier poster mentioned, multiple carbs on a stock engine will not help much. If you install PROPERLY SIZED AND CALIBRATED duals on a stock engine; expect 3~5 percent increase in HP and 3~5 percent increase in fuel economy (obviously not cost effective).

Put two STOCK carbs on a stock engine and expect 5~10 percent LOSS in low end torque and HP, and 15~20 percent loss in fuel economy.

The key is in the selection of the carbs.

If you truly believe that "one size fits all", try walking a mile in your spouses shoes.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop