Mike a size 50 jet is small for a 235 with a Rochester B and ethanol laced gas. Usually 58 or 57 is what I've seen with a couple of 56 sizes in there when the 235 was a younger engine (maybe 1950 year or so). A 50 jet will make your carburetor run very lean. At this point it is very hard to unscramble the egg, but as I recall the smaller jets were common in the 216 engines...size 51, 52 jets, etc. If I was going to use a Rochester B or BC on a 235, I'd start with a 57 size jet and then increase to 58 if needed.
But honestly before I spent one cent or any more time on a rebuild kit for the Rochester I would consider a Carter. The design is much better and they don't have that wacky power circuit which with unleaded/ethanol gas is just about guaranteed to get stuck in the open position.
If the carburetor you have was really intended for use on a 235, then I'd guess your air horn and possibly float bowl are warped (which is so common with Rochester B and BC it should be automatically expected) and if so, I would bet your power circuit is in the failed mode (meaning your power valve is open all the time). If somebody has put a 50 size jet in there, it could have been because they didn't understand what was happening with the power piston/power valve, didn't know what to do with it and they were trying to get the thing to run leaner. Or it could be that parts have been mixed up a lot in there.
Good luck.
