I found the thread for the 557 that broke. I agree it could definitely could have all been a crack from the dowel that caused that. What was odd about that one was one side of the saddle broke and left the other side when the crank broke. I have never seen one fail like that in one of the weaker blocks. That is about the only 557 I have seen that the crank may have let go first. Some others commented similar thoughts in the thread.
https://forums.maxperformanceinc.com...&highlight=557
About a year after Mchell broke his crank there was another thread with his new engine showing the timing marks on the harmonic balancer were off an 1” or 2”. It was an aftermarket balancer, I don’t know if it was the same balancer from the engine that broke the crank or not. Seems like too much of a coincidence though.