350 in 96 1500 locked up tight. Just driving down the road and it stopped. I tried turning it over and it moved the pulleys maybe a 1/4 inch and just stopped. I replaced starter cause thought it was bad. Makes the clang as it engages the teeth on the flywheel and nothing. I tried to turn the crank shaft with socket and it is froze tight.

I never had a chevy engine do this. I have spun lots of bearings in them and thru rods thru the oil pan but never locked one up from normal driving before. There was no sign of troubles from this engine at all. Now I am thinking I might of dropped a valve. But I have never done that before on my older chevys. After I pull the covers and check, Has anyone else had this problem and what else should I check for after that? Pull the oil pan and start loosening the rod and mains one at a time till it turns would be my only other try after the valve check.