Cool looking Super Sport you got there. Do you know what kind of aftermarket muffler is on there? I'm working on A '75 CB550 Super Sport myself, the pipes are good but the muffler is rusted through and I want to find something to replace it and keep the 4 into 1 pipes.
By the way, since you are getting rid of the stock tank, might you want to part with the gas cap? Mine has gone missing.