Agreed. The Chevy 60° V-6 engines commonly develop leaks at the intake-head flanges, and that can be repaired. This can happen with any engine, but they seem a bit more prone than the Buick 90° V-6.
No engine is "bullet-proof" but I would consider the Buick 231 to be "highly-bullet-resistant" compared to most engines produced through its nearly 50 year production history.