If the power piston isn't sticking (maybe due to your fuel additive...phase separation is a problem as you seem to understand), then that is a good thing. The fundamental problem is there is suction present in the power piston cylinder any time the engine is running so it will constantly suck gas up in there. And that is the problem. If GM had designed the carburetor with more than 4 screws holding it together and if they had put the power circuit outside (still controlled by vacuum but not immersed in gasoline) the carburetor in my opinion would have worked better. I even gave thought to designing such an adaptation, but the cost and the time are the problems there. In all fairness, no...it is not a good design. It makes me wonder if the person who designed it just bought the books for engineering classes and never attended. However in complete fairness, do any of us think GM thought those carburetors would still be in operation this many years later? I expect they would have been surprised to see people using them for 15 years much less 60+. So there's that. But the YF design is more effective in all ways and unless the thing just flat wears out there is really no reason that carburetor can't be used for a very long time. Jon H (CarbKing) does have some resistant diaphragms. Those will help a lot.
From the standpoint of "something more reliable and with better performance -- something I don't wanna keep screwing around with" the Carter YF is probably going to be a very good alternative. Are there better ones? Some would say the Stromberg option is good but it usually isn't cheap. And about 10 or so years ago there was a fellow here who adapted fuel injection to his 235 and claimed to have driven it something like 30,000+ miles...much more than the typical tinkering with the over the counter add-on experiments. As I recall he lived in Odessa or somewhere else in West Texas and he drove the truck all over the place. His analysis? It started easier and it ran okay but he never got it to run lean enough and it got horrible gas mileage.
