You'll be up for a reasonable amount to freshen up the old motor and once you do you'll still have an old motor.Are parts still readily available. Youll need New bearing kit,Gaskets,rings etc. How about taking the heads off and inspecting the bores. That may give you some idea about the block condition.
Has it ever had a freshen up???
I kind of like the idea of getting it up and going again just for the heck of having a motor of that age but monetary common sense may dictate otherwise.