If you have a broken piston on an engine with that few miles/time, I wouldn't be taking a chance on simply replacing ONE piston/rings. As a minimum, I'd likely pull the other 7, and inspect. Perhaps dye-penetrant, or at least something similar. I've had too many 'bad piston' experiences. And, if ONE is bad, I'd figure the rest are 'suspect'. How may times have I heard a 'knock in the crankcase' audible externally, and especially audible if you put an ear to the oil-fill tube. And, the 'knock' turned out to be from hearing the combustion through a cracked or broken piston. And, almost always, on flathead Fords. One exception, I once correctly guessed a broken piston on a Porsche six cylinder (almost new car at the time). The dealer who tore it down/fixed it, was amazed at my guess, and I told him it was based solely on flathead ford experience.