Cracked j heads

I used some block sealer back in the 80's on a Ford 400 that froze and broke the block in the left front corner from top to bottom. It actually worked, I was amazed because it was a very long crack. I know it worked for 5 years because I seen the car all the time.

I have never seen a crack in a head in that spot, I think it must have froze at some point.