hate to hear about your broke engine.
I think the rods may have been fatigues if you had used them for 8 years prior to this build. I used to race Hemi's in Super stock and never had an issue for the first 3 + years running 3 nights each week and turning it 8000+ every trip down the track. Then we broke a rod in my good motor and went to the back up and it later broke a rod too. I had rebuilt the rods every winter in both motors with new bolts on a regular basis, but metal does fatigue after a while of continuous cycling.
Good luck with the new build.
Jerry