Battery cables -where does the negative go?

I think the correct answer is...wherever the assembly person bolted it to. I’ve seen lots in that untapped hole you have, and more than my share on the front exhaust manifold bolt too. I can check the 65 273 I have at the shop on Tuesday.
Thanks Cosgig!
I appreciate that. Funny how a simple question about a mundain thing created this large of a post and this much help.

I’m building not a 100 point restoration but a “period correct” looking 66 car. So all I can get correct the better.