Damsel in distress

Thanks for your advice... if the oil sending unit is bad would it not start? Also how do I check to see if it's bad. The wire definitely is because it's about to snap in two.

Also why when I had at least lights before getting battery charged and now have nothing.... I've cleaned the cables and battery post with wire brush as suggested even though they arn't dirty and look some what new.

I just find it hard to believe that I blew a rod when everything I read about the slant 6 is that they are basically unbreakable and I can't see or feel any holes in engine