That's a very accurate observation. Over the past 50+ years, I can remember several factory multiple-carb setups, and virtually all of them shared one important feature- - - - -they were all progressive-throttle setups, where the extra carb(s) only opened up at or near full throttle, and they opened very quickly to allow extra air volume to the engine at wide open throttle. The early-50's Buick straight 8 engine had a twin-carb option, and so did the Hudson flathead six. Oldsmobile, Chevy and Pontiac V-8's in the late 50's had 3-2-BBL setups where the engine ran on the center carb except for full throttle, then the outers opened up fully with vacuum linkage. Corvair had a 4-carb setup with the second carb for each cylinder bank either wide open or off. None of the extra carbs had idle mixture circuits- - - -they didn't need them. Chevy, Chrysler, and Ford offered 2-4-BBL V-8's with synchronized throttle opening, but they all used much lower CFM carbs than their single carb engines. It was easy to spot an early Corvette with a 265 engine and two 4-barrels by the blistered paint on the hood from the carburetor fires.
I worked on a lot of marine engines in the 50's and 60's with multiple carburetors, but they only ran well at wide open throttle. Marine engines don't need low end torque or midrange flexibility in traffic- - - -they're either idling or running full throttle, for the most part. Installing an aftermarket dual-carb manifold, or more, and using two or three of the same carb that works in a single application doesn't make very good sense.
Jerry
