I was going to do the very same thing as I found a super nice 230 thats been rebuilt. The only difference is the crank and rods. Same everything else. Just has a 1/4" longer stroke. Actually 0.28" I just looked it up in the book. The heads are interchangable as I remember. Both are great engines and last forever. I would have a valve job done and port out the exhaust port or what is called gasket matching to help it get rid of the heat faster and makes your engine live longer. Its worth it. You know, if your crack is on the outside, usually it can be welded with a stick welder with a cast iron rod or nickel rod. My friend did on a large farm tractor and ran it for years. It was a big 6 cylinder diesel with a big crack on the outside. Just a thought. I wish you the best on wahtever you decide to do. Henry