In the 17 Mar 1970 issue of Cycle News there's an article by Russ Darnell on Charles Curnutt. An interesting photo in it shows a set of experimental 8" travel Curnutt dampers fitted to a 250 Husky.
Seeing that reminded me that the Winter 1971 Motorcycle Sport Quarterly had an article on the Buck Smith/Joe Robert's "Superfork" modification (retaining only the stock sliders) to Triumph forks that gave 8" of travel.
The suspension revolution was already in progress.
cheers,
Michael