Full disclosure, I have a Frankenstein Carter YF. The top half is a 964 and the bottom half is for a 235, likely a YF2100.
The '53 full pressure 235 runs extremely well with it. I also have a Genuine YF 2100 which I use when the ethanol eats a hole in the accelerator pump diaphragm.
I have swapped them out several times as the diaphragms go bad over the 14 years I have had this truck, and the Frankenstein carb results in better overall performance which you can feel in the seat of the pants compared to the YF 2100.
Neither of the carbs cause sooty plugs. As far as any sign of a lean condition, I am not seeing that either.
