Put some updated water pumps on it (like Skips), run a really good radiator of the right capacity, run thermostats, run anti-freeze and don't overheat the engine. With a good cooling system, it should not run any hotter than a stock engine. My 284 cube flathead runs at 180 . . . and I've sat in traffic for an hour on a hot 90 degree summer day and it never got over 192.
What you don't want to do is overheat the engine, boil it, throw cold water in the already overheated engine block and then wonder why it cracked.
