[ceslaw]

For what it is worth, I put a 28 ounce flywheel on my crate engine, the builder having confirmed in writing it was a 28 ounce balance. Finished the car. Took it to the track. Vibrated something terrible above 2500 - 3000 RPMs. Sidelined the car. Called the builder the following Monday. "Oh that is a zero balanced engine. Yup, positive. Zero balance." Tore it all apart. Sent the flywheel back to get it zero balanced. Put it all back together. Vibration gone.

So big crate engine builders can goof.