Those heavey old TRW's with stock rods under a blower...

Yes, that is a catastrophy looking for a chance to happen. Even at only 6 PSI. I could blow that motor up without a blower, I'm good at that.

Think about it, those rods are probably over 40 years old. What punishment did they suffer in a past life?

If the builder used those rods and those pistons, this was obviously a budget build, so they probably didn't mag the rods for cracks either. There is no sign of oil starvation or bearing seizure, it's not a stroker so there is no chance of clearance issues, I think the rod was just fatigued and/or overloaded.

Blower motors need the best parts. That way, when you blow it up, you know you really acomplished something!