Light rod knock in a Durango 5.9... is it terminal?

My grandpa ran Pennzoil 40 weight in my truck. He racked up 350k miles on it before giving it to me. And he currently has 460k miles on a '96 5.9 ram. It smokes, leaks, but runs decent and has had Pennzoil straight 40 weight oil since the warranty ran out.

I had the no 2nd gear issue on my 727 in my dart. I couldn't adjust it so I pulled the pan and found the band anchor laying in the pan! Reinstalled it, adjusted it, and it shifts great still.