Battery cables -where does the negative go?

Dicer said

Here's another shot of battery cable....I have to ask did you check the other head back side to see if its tapped?

View attachment 1715240378

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I did check and it is not. But the rear of the drivers side head is- for the kick down bracket. And the front of the passenger side is for the alternator bolt.

Sounds like a mystery for the Hardy boys and Nancy Drew!