Just remember that antique car parts are not subject to taxes/duty. My grandpa used to ship his parts just south of the Border and drive into the US and bring them back himself to save on brokerage fees.
Someone needs to explain that to the border guard. He wanted to see receipts. I had 8.75" axle parts. From cars I parted. Basically one axle, disassembled for easier transport. He let me through, but wasn't very happy about it.