got a new 408 maybe 300 miles on it been setting for bout 4 months and pulled it out to wash, it was idling a little high so i did a quick rev to bout 4000 rpms to get it to idle down and this horrible clanking started until the car died, now it want turn over like its locked up any easy ideas hope its not internal??

 

Can you hear the starter at least?

Really it's just a guess for us, if the starter is still working and the engine won't spin at all I would have a friend check to see if the balancer is spinning at all.

There's really only a couple places that would make metal to metal clanking, either valve train or rotating assembly..

You could always pull the valve covers and take a look inside and make sure you didn't break a rocker and spit a pushrod out.. It has happened to me during regular driving.. I didn't have the trunion upgrade back then..