[CMcAllister]

As a side note, we ran stock bottom end, steel crank 340s to 7800 for a long time with none of these issues. Cut an iron 360 crank for in a 340 block to get some cheap stroke, and almost right away, spun a bearing and broke the rod. Put a new stock bottom end 360 together and have the same issue, although I paid attention to it and would fix it as needed rather than blow it up. Something about the increase in stroke and the iron crank that doesn't like to be spun beyond about 6800. Some folks get away with it for some reason.