Stock Stroke 340 Build with NC Engine Builder

This dyno had a similar issue not long ago, but fortunately the shaft broke as he was just warming up a engine, not during a pull.
Mine broke right around 5000rpm, good thing I had a 7000rpm+ SBC on it cuz I'm pretty sure it went 7100 as I slammed the throttle back. I kept the engine running to confirm no issues. J.Rob