The 230 is an entirely different animal from the 235. To use a 230 in your '59, it will require replacing everything thats in front of the tranny and making motor mounts. It's possible that someone makes mounts for this swap, but I don't know who. Possibly check with Tom Langdon or Buffalo or Chassis Engineering...
The 230 is definitely a better engine, but if you can, a 292 would be even better.
