Not to start a war over the "new" and "old" carburators (because I think they all are good) BUT the Offy and Clifford manifold are made for the small base 4 barrel cars including the Rochester 4GC, Carter WCFB and the Holley 4200 aka teapot. These can still be found and all flow, from what I heard, around 350 to 375 CFM. The Rochesters and Carters are found on early 50's Cads, Olds, Buick, Packard etc all in the 300 in+ range. Kit for these carbs exist at fair prices and are easily adjustable with jets or metering rods. I would not use a holley 4200.....
I am currently replacing the teapot on my 56 Ford Victoria to a caddie Carter. It will still hide under the "stock" air cleaner
Hey just another option.....................