[kamesama980]

could also be bad pistons/rings if they're hot enough to stick to the cylinders. Either bits welded to each other (rings to piston or bits of AL from piston in the rings) or just scuffed to the point they won't seal. Depends on how bad it overheated and whether it stalled while driving and seized later or seized while driving.

Valves usually don't seize open but if they did, the cam will force them open, after which they might stick that way. That's easy to check though: just pop the valve cover off and see if they follow the cam lobe.

If you want to asses the engine's condition before starting it, you'll need a real compression tester and leakdown tester, even cheap homemade ones. if you don't want to go to the trouble just fill it up with some water and fire it up. once you get it running you can drain some and add anti-freeze.