[frnkeore]

If it was under a pile of loose ash, it cooled down, very slowly and will now be in a annealed state. Not a bad thing for cast iron.

As RotorWrench states, you can successfully weld cast iron by heating it to it's critical temp (the whole item not local) and then slow cooled (anneal). Heads have been repair that way for a 100 years and is the best way to do it.

You don't hear about blocks repaired that way, because it takes a large furness to heat them. It hard to find someone to do heads that way, in our "modern times"?

Like has been said, I would inspect the for cracks and then pressure test but, it sounds like there is a good size crack with the " I also had an old braze repair disappear out of combustion chamber" comment.

As for the cranks, have them checked for straightness and what ever hardness std applies and regrind if possible.

PS
Where are you in Nor Cal?