PasterMatt - 4 things:
(1) Rochester used a number of different sizes of jet in the Rochester B for the 235. Your last post stated it was a 1961 carb which should be tag number 7015011, and the Rochester specified size for this carburetor for the 235 was 0.055. Repeating: different versions had various size jets from (memory) 0.054 to 0.059. The size of the FUEL jet corresponds to the size of the AIR BLEED in the specific carburetor. This is why for best results, it is imperative that one knows EXACTLY what carburetor with which one is dealing. The earlier (1958 and before) carbs were jetted richer.
(2) NEVER (and I detest the use of the word "never") believe what is stamped on ANY jet from any company. Folks have been drilling jets oversize since 5 nanoseconds after the first carburetor with jets (the first carburetor didn't have jets, it has a wick) was released.
(3) I don't believe an improper sized jet (if in fact it is improper) is the cause of a stumble on switching gears. If the carburetor is the culprit, then a stuck power valve or trying to use a non-leather accelerator pump with ethanol fuel would be two possibilities. Another possibility would be the advance mechanism in the distributor sticking. Too small a jet would cause the engine to run poorly, not "did fine in 1st gear".
(4) Another option, should you not wish to go with a Carter, would be to remove the hood, and the Rochester. And UPGRADE to an unemployeed 15-year-old standing on the running board and pouring fuel into the engine from a leaky boot!
Jon
