The 3800's bottom end is pretty stout, as it is. Kudos to GM's over engineering it.
It's not so much a question of how much power it can handle. It's all in the tune. Some uncontrolled knock in a high HP setup will tear it to shreds. You'll probably find most high HP failures come from detonation and not the HP directly.
Two types of forces at work in an engine. Inertial forces (inertia of the parts, specifically pistons and rods moving back and forth), and power forces (force of the expanding gases pushing on the pistons, rods, and crank). Inertial forces are many times that of power forces, so increasing power doesn't add that much to the total load felt by the hard parts. If that makes sense.![]()