It wasn't just the forks. I had a '73 Mach III that I put 6" overs on from Forking by Frank, (remember him?), and extra braces. I do believe the frame itself had a noodle or two in it.
Also went with Denco expansion chambers, cut the pistons, air cleaners, etc. Remember the power band of the Mach III? This made it worse. It went from 2 rear wheel HP to about 80 like a light switch around 6000 rpm. It was a high speed wheelie machine fer sure.
Amazingly, in almost 100,000 miles, I never wrecked it, not even so much as laid it down.
Still more amazingly, I seen somebody out riding it around about 10 years ago, still had the 6" overs on it. Same paint, no perceptible dog-legging, that bike must have come with it's own guardian angel.
I had some of Frank's forks on my '48 Panhead. I replaced the entire front end. Thanks for giving me an opportunity to post the picture again.