We have seen more of these issues and we have become more and more familiar with this. We actually witness a block break in front of our eyes on a brand new engine and starter in a Hyster while testing it before sending it back to the customer. We have surmised that A. the GM block has a poor design. B. We have only seen it occur on propane units. C. Nearly all manufactures have come up with there on "fix". Cat/Mitsi time delay, all the others brackets of different sizes and arrangements. One thing to watch out for is we have ordered and compared different manufacturer bolts from both industrial and automotive applications. The outer bolt hole in the block sometimes has casting slag near the top so a bolt slightly too long will bottom out and crack the block as well. The bottom line is there is something or a combination of things that cause it and even with all the parts correct it can still break.