have never had a rod fail. Did bend a few valves though. I have been around small block mopars most of my life and dont ever recall seeing a stock rod failure but I am sure there are many. .
I've only seen a few fail and I couldnt really attribute it directly to stock rod use. Mopars are know to have good stock rods. That's why Chevy had to add better rods to the higher hp engines. They broke tham a lot. From what I've seen the majority of big blocks break as a result of the blocks giving up, rather than rods or crank.