alright, took me way longer to get to it but. we have it all sealed up, ground it down JB welded it and tossed a bottle of sealer in when I fired it back up.
JB really slowed it but it took the sealer to stop it completely. even put a second coat of JB as an insurance policy. ran it a while no leaks, so I topped it off and put it away for the winter with a good 50/50 mix. should be ready to rock in spring. thanks to everyone for the ideas and suggestions!
Well, there you go; sounds promising. Keep a close eye on it for a while, especially when the weather gets hot. That crack must work up into the block at an angle. That sealer will tend to plug the radiator core so don't overdo it.