All I can add here is, I've seen precious few broken connecting rods. More aftermarket than factory and the factory ones always caused by "something else" like a broken rod bolt or "something" that just got in the way. I've never simply seen a factory rod "just break".
A good reference for comparison is to take a standard big block chevy rod with 3/8 bolts and place it side to side with a 318 rod. There’s not as much of difference as you would expect to see there.
