I kind of thought it had well over 100K miles due the the seat wear and other things I saw in your pictures. Don't worry to much about that as the 225 slant sixes are strong little motors that can take a real beating and keep on going. I've seen one still run that had its number six connecting rod go through the engine block wall behind the starter. They use to use these engines if I remember right for the dirt oval track race cars because of their hard running abilities.