The 500/550 combustion chamber is exactly 13cc's. The compression height of a 550 piston is 23mm. 750 rings thickness-1.48mm compression rings, 2.8mm for the oil ring. These are 61mm rings.
cbt is correct a stock 550 sleeve can be bored safely to 61mm, but no more. At that diameter, there is no room for an overbore, one time deal.
It is time consuming designing the piston crown considering dome height, valve relief depth, compression height, etc. etc. Of course it can be done. Who are you talking to?
I believe Dynomans pistons are CP... very good quality. I talked to Buzz two years ago and he was only thinking about these. I went my own direction, but by the time I was done adjusting all the dimensions mentioned above, that $600 price including rings is worth it.