I would never run any heads out of the box without checking them, aftermarket or OEM for that matter. I have one of the old sioux vacuum testers to check valve seal, you would be surprised how many new heads will not hold a vacuum. Funny thing is they all hold a vacuum after I touch up the seats. And I see lots of spring pressure ranges, cheap aftermarket to expensive, especially with a flat tappet camshaft, you have to verify the spring pressures. And I am relating issues that people bring me to fix after the fact. So I don't see I guess the ones that work out of the box, mainly the ones that don't.