Good question. I didn't explicitly stated that I'd like to replace my sprockets too. They've probably got 13,000 miles on them with the original chain, and I could also take this opportunity to change the gear ratio for a more favorable RPM at speeds (maybe).
The top speed on the CB550, is achieved only when the final gear ratio allows the engine to make enough torque to overcome the wind resistance.
The CB550 doesn't have a lot of torque. And its best HP is only achieved at higher RPM. Check out the HP and torque curves. Max torque occurs at around 7500 RPM. Honda says 38 HP at 8000 RPM and top speed occurs at 8500 RPM, when wind drag and rolling resistance power consumption equal the power produced by the engine.
In other words, lowering the RPM with a sprocket ratio change is counter productive. It might make your ears feel better. But, the engine will just be in a higher working, less efficient mode.
It likes RPM and works best when it has more. Better to just get used to it and accept the bike for what it is, or get a different bike.
Of course, if you must have a loud exhaust modification, that high RPM noise can cause rider fatigue, and draw more attention from local law enforcement.
17 Front, 37 Rear sprockets.
Cheers,