What was the real octane of the high test / high octane of the late 1960's? Here's Sunoco's data

From Sun Oil Company, J Ziegler, Sales Promotion 1966
For the cool advertisements of Sunoco, some more new ones just added: http://justacarguy.blogspot.com/2009/05/sunoco-260-advertising-makes-me-wonder.html

Sunoco 260 advertising.. . makes me wonder why anyone would feel it necessary to advertise gasoline

A different kind of ad for Sunoco was the jacket: http://justacarguy.blogspot.com/2006/11/sunoco-260-race-gas-at-gas-station.html