I would suggest cleaning your engine really good to see exactly where the leak is coming from. The places on a 550 where the head gasket leaks is the very ends on the sides of the engine where the jugs and head meet or the very front center but not as much as the sides. If your pucks are bad you will see oil coming through above the head gasket level usually at the head bolts on the exhaust side (front ) of the engine. It's a pretty easy fix and probably worth the time to replace the pucks, the valve cover gasket and cam cover gasket. I used a bit of marine Perfect seal around the edges of the pucks for extra insurance against leaks.
I would suggest buying a whole top end gasket kit, It has everything including head gaskets and base gaskets carb intake and valve cover O-rings, starter cover and points cover seals, valve cover and cam cover seals, cam end cover o-rings, pucks, valve stem seals, etc etc, everything you will probably end up replacing on a 35 year old bike anyway.