Cracks, rust.
I locked up #6 because of leaking manifold. Tried to stretch them one more season and that was a bad idea.
Luckily got it un-stuck and running just fine.
I think still jumping in deeper than you need to right now.
I saw you pumped new gas but did you run it on a portable tank? Also might of missed this but are you sure you got the motor at TDC before even starting the timing procedure?