I won't remember the details clearly by my '70 chevy lost a "freeze plug" in the winter 'cuz my antifreeze measure was faulty. I do remember desperately pouring water in, that had ice in it. The miracle was somebody telling of a shop that would fix it. I drove, stopping every mile or so when it overheated and poured more water in. they fixed it just fine and I got to use it for some years after.

Now, "freeze plug" is not what it was designed as, it was a lucky accident from the block casting process.

Nils K. Hammer