I have a buddy who's Dad let a block freeze on an old Cat D9 bulldozer. Was gonna cost a ton of money to fix. Instead, he mixed up some JB Weld and filled the crack. That was over 25 years ago and he's still using the 'dozer. Your results may vary.
Jb Weld only lasted a few hours when I used it to weld my clutch drum to my drive roller. Then again that is as long as the regular parts lasted. I would say pretty strong stuff.