Loud grinding noise: won't restart

I was driving my 1970 valiant today when there was a loud knock. I immediately put the car in neutral and the engine died. After getting the car home, I tried to restart, but only got a grinding noise. I checked my oil, which had no water iin it. I am thinking that I may have spun a rod. I took my starter off and observed the fly wheel and starter wheel; both still had teeth and did no show any signs of missing any.