May I dive in here and ask a quick question - apologies for going off topic slightly.
A previous poster states "only a factory can zero time an engine". The engine of the aircraft I fly (also a Continental) was, apparently, zero timed after a "top end overhaul" but I'm fairly sure this was not done by the manufacturer.
Therefore, I assume it would actually be misleading to describe the engine hours since top end overhaul as hours since zero-timed??