Balancer slides in on install

No, this isn't a Pontiac, but it works exactly the same: conrods, crank, pistons, timing chain etc, etc.

If you do the bolt up tight enough, the dampener won't move [ it is not a balancer, it is a harmonic dampener that has been balanced ].

There has never been any problems such as broken cranks on Pontiac engines, any more so than on other engine brand, because of the way the dampener is retained.