Dual carbs won't make it run cleaner, stronger or better but that is an interesting way to ask the question.

Unless you are prepared to spend time and a lot of money modifying the camshaft, doing a bunch of head work, valve work and improving the exhaust system, you probably will wind up with less horsepower, less efficiency and lower miles per gallon. You may also get flat spots, odd acceleration and your low and midrange use will suffer. If you do all the work and make all the changes, you'll be left with an engine that likes to run at wide open throttle. Maybe...or maybe not, depending on how much homework you do...maybe you could improve things a little bit if you had 2 very small carburetors (which in total were equal to the CFM your engine was designed for (roughly 190 CFM). But if you just go out and buy a manifold and put a couple of Rochesters on there I think you'll just make it worse. You might make it much worse.

In my opinion the best thing you can do is find a good (or better yet new old stock) Carter made for the 216 and use the stock manifold. YF 964s or 965s are good ones. If you have a Rochester on there now, either of these Carters will be an improvement. There should also be some W-1 models that would be good. Good luck. Search this topic and I think you'll find it has been pretty well beaten to a pulp here.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end