Biggest concerns are around shit paint jobs from the domestic manufacturers. And of course your bearing and all that. The shame is that at 400k it might cost you more than the car's worth to get to 500k.
Lol. I had a guy tell me once that the government was lying to us, and that what was inside your motor was actually a nuclear reactor! Cool part was, he wasn't wrong about keeping the engine COOL to prolong it's life. So stay updated on your engine oil changes.