I took my '64 Polara 500 convertible to Carlisle to sell a few years ago. This was a U.S. car, built in Detroit. In short time, I had an interested buyer who gave me a sizeable deposit on it. I had to explain that I could not actually sell it to him there, that day, because I had not brokered it across the border, and did not have the required import documents. He would have to buy my car in Ontario and be the importer to U.S. He agreed to this.
In the meantime, I obtained, filled out, and signed required forms to declare this car did not need to confirm to modern emission and safety standards due to its age. I met the buyer near the border crossing, where we transferred the car from my buddy's trailer to his. After final payment, I gave him a notarized bill of sale, and the signed vehicle portion of my Ontario vehicle ownership document. I told him that U.S. Customs would make out import papers for him, and he would have to give the emissions and safety forms to them. He was not required to have the papers at the border 72 hours ahead of importing the car, as we in Canada must.
Speaking to him a couple of days l
ater, he said the process at the border went smoothly, only taking about 15 minutes. No taxes, fees, or anything.