I own two 60 Imperials. If it were mine, I would find another engine & restore as original. I doubt many people would care about numbers matching on an Imperial.
I agree with John's message above.
Also remember that the numbers on the engine are not matched to a specific car. The closest "match" between the engine codes and the car will be the year date. Finding a 413 from almost any 1960 Chrysler product will be a "numbers matching" engine.