Back when I was rebuilding my '77 CB550F, I purchased a set of carbs off ebay. As soon as they arrived, I cleaned them up and replaced the guts with all new parts (jets, needles, etc.). They run fairly well I think, but a little rich throughout (according to the dyno).
The carbs for my bike should be 069A.
The other day I was fiddling around and noticed the stamp on my carbs. 627B. Our FAQ indicates these were for 1971-1973 CB500s. So now I've got CB550F needles, jets, etc. in 627B carbs.
It doesn't seem to be a problem, I'm just wondering which settings I should use for things like jet size and idle mixture, as they are different between the 2.