Hi Soul Trader. My sympathy for the radiator problem
. I live north of Seattle in farm, race car & logging country. I just took a huge radiator into our radiator repair shop for a check up prior to placing a new engine in a Crown bus. My suggestion is to have a replacement core put in your present shell. The radiator man told me that with the new core material he can lower the operating temprature by 25*-30*. A good shop will make it work using your present core as an axample. Just check around your area and find a shop that will replace the core with a new or custom or universal one. It may take a few calls but will be worth your trouble.
Good Luck, J.B.