If one of the rod bolts was loose you would think there would be a rod knock long before it let loose?From your other pictures,it looks to me like one of those rod bolts was snugged down but not torqued down.It then loosened up causing the other one to break.Hopefully the block isn't killed.Another possibly is that the broken bolt streached excessively during torquing and caused the failure.
I noticed that but didn’t think it would be an issue but you have a point. I wonder what grade? Quack!Castle nuts on the rods. Really!!!
Gary....I know someone who has a spare 348 oil pan!!!!!!!
Castle nuts on the rods. Really!!!