There are a lot of theoretical opinions on the one carb vs two carbs but not a lot of empirical evidence one way or another. However, one such piece of evidence that is available for review are the results of tests done in 1955 by the well respected Racer Brown. With a vette exhaust manifold, a McGurk 2X1 and a pair of Stromberg one barrel carbs, the power increase of an otherwise stock 261 motor was measured to be 14-18% more then stock. The article appeared in the May 1955 issue of Hot Rod Magazine.
Back in the early 1990s, pre internet, I received permission from the late Grey Baskerville at Hot Rod to publish the article in Inliners International's 12 Port News (and it was published). So this article has made the rounds over the years and to my knowledge, no one has disputed those findings, or done any additional testing.
http://www.earlycorvettes.com/linda/mcgurkhotrod/mcgurkhotrod001.pdfOver the years, some automotive manufacturers have also added a second carb as a way to obtain a little extra power, like Hudson's compound carburation set up. I am no automotive historian, but I will bet there have been others over the years.
This business of opining that a chevy 6 motor will make no more power with two carbs then it does with just one carb is just not in reality.
