This is the answer that I got from a Facebook group :
Tim Hubler You're all wrong. That bolt was used in 1967 Toros equipped with the K-50 option, the Climatic Combustion Control air cleaner. That is the source of manifold vacuum that operates the vacuum controlled doors in each snorkel.
Then this post :
Ralph Hupfer OK guys, I stand corrected. IT is a factory bolt, on 67 with CCC. I have been in Olds parts from 69-80 and have never seen or had a call about it. I did not believe it. You gotta be kidding! Here's the part number for it. Ha
So I don't really know as I had so many different answers. But I have looked the manual and nearly every sections, I don't see any mentions of that bolt or any diagram where a vacuum line is plugged on that bold. But on the other hand, this is not the first picture of a 66 that I see with this bolt, for example, on the website of Sparky http://www.sparkyscarbs.com/October%20043.jpg
What to believe, what not, does it even matter ?
