[Mark Charlton]

Also, from: FAQ's

Vehicles Over 15 years old (except buses)

All vehicles (except buses) that are over 15 years or older by the date of manufacture are exempt from the Registrar of Imported Vehicles program. You must be able to prove the age of the vehicle to a Customs officer.

Kit Cars

A kit car is not permitted entry unless it was assembled more than 15 years ago. You will be required to submit proof of the age. Registration documents will have to show that the kit car was registered more than 15 years ago. The date the reproduction was assembled is the age of the kit car rather than the model year of the reproduction.

This is relevant also: Importation of vehicles into Canada from countries other than the United States

From Transport Canada:

PROHIBITED VEHICLES

Vehicles Manufactured for a Foreign Market

31. Vehicles less than 15 years old and buses manufactured on or after January 1, 1971, that are manufactured for a foreign market (a market other than the United States), do not comply with the Canadian Motor Vehicle Safety Standards. These vehicles are permitted entry only if they qualify for one of the provisions stated in paragraph 29.

Grey Market Vehicles

32. Grey market vehicles are foreign-specification vehicles that are re-certified by a United States company. They were originally manufactured for the domestic market of a foreign country and were subsequently imported into the United States where they have been modified to comply with the United States safety and emissions standards. Grey market vehicles may be identified by a label affixed by the United States company that altered the vehicle, indicating that they have been "imported," "altered," or "modified" to comply with the United States standards. These vehicles may not have a certification label affixed to them. Grey market vehicles are ineligible for entry to Canada and are to be processed in accordance with paragraphs 40 and 41.

Kit Cars

33. Kit cars are treated as vehicles whether they are presented for importation as a fully assembled vehicle, or as an unassembled vehicle in a kit.

34. A kit car does not meet the import requirements for the SOC label, the 17-character VIN, or admissibility status. Therefore, it is not permitted entry unless it was assembled more than 15 years ago and the importer can submit proof of age, e.g., a registration document. The age of a kit car is determined by the date the reproduction was assembled rather than the model year of the reproduction or the date of manufacture of a donor car. If in doubt, contact Transport Canada for a determination on the kit car's eligibility.