Ive been off line a bit, But I did look at that listing on Satans swap meet. As another lister has noted, the seller is a "Butcher shop" and killer of cool bikes. Sad! But that IS a Superflash frame. I have one that has been modified but was not a factory job.
In case the OP was wondering its for room for bigger carbies,, I hope someone can salvage it, sadly the soulless heathen who parted it out ALSO has the rear section that goes to it in another auction. WTH???
As to rake and mods,, there is MUCH debate in the Triumph world on this and the factory did a few different steering head angles for more responsive turn in, However must have been some complaints as maybe TOO responsive as they changed it back. 1965 is the golden year and for a unit Triumph 650 is the one everyone wants for racing. Allegedly Ray Hensley copied the 65 geometry for his Trackmaster frames.
Another interesting mod before cerranis and betors became common was to mix and match fork parts. BSA Triple trees were modified, there is an article about Rickman frames and desert racing where Bud & Dave Ekins talk about setting up desert racers and how they would modify BSA Trees and then slide the forks up and use pinch bolts. This drops the nose a bit. I found it in a old cycle world magazine reprint from the early 1960s. I can dig it out if someones interested...
* EDIT* I tried a google search, Its June 1964 issue and its posted here in this website,
See:
https://selvedgeyard.com/2012/02/25/steve-mcqueen-doin-it-in-the-dirt-triumph-desert-bike-by-bud-ekins/#more-28479**EDIT NOT the article I was looking for,, but its still cool.
More in the same vein and talks about a variation, using BSA Trees with Cerranis but still not the article I am looking for, but super cool review of how to set up desert sleds. (And a nice plug about how good BSA Hornets are!
See:
https://selvedgeyard.com/2010/10/22/steve-mcqueen-66-popular-science-what-i-like-in-a-bike-and-why/Eh, Ill find it, but they would cut the top trees and make pinch bolts on the sides, using different fork tubes they would slide these higher into the trees and then clamp them. Variety of forks used but all were using BSA trees until much later when Cerranis and others started offering light weight alloy trees and some with rake or trail set up in them. I had a friend with a Boyd & Stellings setup and the neck was totally adjustable. Really an unusual looking bit of kit.
