Scott S is correct, 400F pegs, linkage, brake lever and 550F kicker.
This is a set up that will allow 400F exhaust on a 350F. It should work on a 550 as well -- the peg mounts are the same, IIRC -- although it also depends on the exhaust. I tried on my '75 550K with a Kerker 4-1 and no dice. The brake lever as it is may protrude a little, as it was meant to clear the 400F's collector.
For the 350F, the linkage is indeed flipped over once, and I usually grind a little off of the ball joint to make it work more smoothly. And the linkage is adjustable in terms of length, there should be enough adjustment to work on the 550 (again, IIRC).
And yes, people use these as sort of semi rear sets witha stock look -- they put the pegs back about 6 inches. I had hoarded about 5 or 6 sets of these but wound up letting them all go when I moved to Mexico.