My 46 with a single speed 6:17 rear and 8.25 tires will cruise well at 50-53. I have had it to 65 but it was screaming. 55 isn't that bad, but 50 seems to be what it likes.
I rebuilt the 235 last winter and it still has the babbited rods with .030 over pistons. It's all stock. Even the radiator is original. I do run up around 190-200 degree's on a very warm day on the interstate, so if it is really hot out I tend to keep it under 45 for long periods of time. I have upgraded to a 12V alternator
I drive mine regularly on the interstate and in town. About 100 miles a week on average.
