Although you could probably tell if the motors were really rebuilt when you tear them down... It IS possible for the motor to go boom after 8 hours if you dont know what your doing... Incorrect rod bearing size (never plastigauged) or incorrect install could cause it. Although it sounds fishy. I have taken a lot of peoples experiences here and plan on being VERY fickle when I buy my boat... Mainly because it will HAVE to be an older boat so it could totally have similar issues!