When a rod fails, it almost always occurs when the engine is running hard. It's like an explosion. The broken rod can destroy the block, cylinder, valves and camshafts, and crankshaft. Basically, a broken rod can easily destory an entire engine.
So please, make sure you have a rod designed to handle the loads you will impose on it.
On a personal note, I once had a rod fail in my car. I had about a half-second warning, then a big bang, then lots of smoke, and zero power. I looked into my rear-view mirror and could see lumps of metal bouncing down the road behind me. I had to replace the entire engine.
