I have looked around for such a beast (stud with different sizes) and have not found a local source. Any ideas? Even if I found one, how would I tighten it?

When I say bore hole, I mean the diameter of the thread part of the bolt that holds the knock sensor in (and therefore the diameter of the hole in the knock sensor), not the size of the wrench needed to loosen it. I imagine that the knock sensors that come stock use an M6 or M8 bolt (6mm in diameter or 8mm in diameter). My M10x1.5 bolt uses a 17mm wrench to loosen it (although 14mm head size is not uncommon).

I won't know for sure if this location will work until I try it.

Thanks for your reply.

Dave