I don't know if there are companies that specialize in rebuilding 235's like there are with the popular V8's, but I know with the help of someone here in the states, you can get a good 235 built by a machine shop and shipped overseas.
If you run out of options, I'll see what I can do to help you. Typically, a machine shop won't have as much of a warrantee, if any, but these motors are stone reliable. I run one myself in my 1952 GMC pick up.
