I have not done that conversion, but have casually entertained it. I am curious to see how a second water pump is added.
Ron C.

Jeff, What pump will pump raw water through the heat exchanger? You will have to add a pump, right?
Ron C.

Another thing to check is the valve lash. It might be hard to check and/or adjust without pulling the engine, but incorrect valve lash can create exactly the symptoms you describe (running until the engine is up to operating temperature, then not being able to start). Based on watching folks restori...