So we finally got our 5.0 to start , which it ran terribleness, it shakes real bad and has a loud banging noise while running , so I figured it needed to be timed , but after doing all that it still runs horrible , and now I started it and pushed it to 2000 Rpm once and now it's locked up , won't turn over or anything.. What could have happened ???

 

I haven't run into a situation as you have, but from your other post and today's recap, your gonna have to pull the engine and start a complete teardown. Either there wasn't enough oil pressure/volume to cool and lubricate or there was a binding between crank and connecting rods.

Sorry to hear of the bad luck.