I've got a 550F kick lever en route from another member. I'll be the guinea pig and let you all know if it clears the folding 400 peg.
Honestly though, there really is no "complete write up" necessary. Remove rider pegs, brake lever, shift lever....replace with CB400F parts. The shift linkage did rub the engine case but I gave it a slight bend and now it's perfect. The only thing that's tricky is the rear brake switch as there isn't a place to hook the spring. I currently have a race wire wrapped around the brake lever that connects to the spring, works fine.