1978 Chevy Caprice

O.K. Your question is extremely confusing. But I'll try to clear some things up for you.

While shoving your transmission into park while the vehicle is still moving is very damaging to the trans, it'll have absolutely nothing to do with your motor starting, or cranking.

And when you say you motor no longer cranks, I'm assuming that you mean it doesn't turn at all when you turn the key?

If not, then first check your bat cables to make sure they're not corroded and that there's a good connection. If that checks out, then your starter is probably blown.

As for the "Scratching" noise, I have no idea what that is, or even sounds like. If it's making that noise while you try to start the engine, then it's probably your starter, and it's bad. If it does that when your engine is running, then there's no telling what that could be.