318 just started knocking???

Wow!.....Andy, I know you feel some sense of urgency, but please take your time to diagnose this issue. Not trying to be a peck3r head, but the rocker shaft bolts would have been one of the last places i'd have looked. I'm sure once you get that squared away, the issue will still be there.

The noise out of know where could be lots of things......A exhaust leak, loose/broken bolts front and rear of the engine, a bent pushrod, a lifter/cam going away, and even worse, a rod making noise? How was the oil pressure when this happened?

What i'm trying to say is, don't jump to conclusions, and take the advice here and methodically figure out what you've got.

Good Luck......That's a really nice Scamp you have.