I'm about to buy a 73 Vette. I believe the odometer is in Miles. The seller has shown me a Ontario Safety Certification with the same reading in KM. I'm a vette newbie. Please clarify if possible. Also, its an original 350 with either 108,000 KM or 178,000 miles. Engine looks good and clean. Headers are orginal. Car drove well. I'm concerned about 178,000KM. Should I be?