On his favorite cars, "I tend to like noble failures, cars where the designer or the engineer put way more into the car than was necessary to sell it, so consequently they weren't successful because they were too expensive."
He points to the Tucker or the Wills Sainte Claire, both expensive, beautiful failures. "The Mustang is a classic example of a car that was successful because it was basically a Ford Falcon that was sexy. When the car was designed, people wanted independent suspension, and Lee Iacocca said, 'Just make it look good, put a stick shift in and bucket seats, make it cheap, and people will buy it.' And he was correct."
Read MoreHot new cars from the Paris Motor Show
On choosing which cars to restore: "I'm like the Mia Farrow of cars. When I see something, a car abandoned by the side of the road, I have to bring it home and nurture it and try to get it running again," Leno said. "A lot of times I buy the story as much as I buy the car. If a car's got a great story or a great history, that's exciting to me."
On using a 3-D printer to make parts: "I think this is the future of manufacturing in America," Leno said, standing in front of a 3-D printer which he now uses to create missing parts.
"You can't compete with Asian countries for $2 a day and no health care, but by using machinery like this, you can make parts with very low labor costs. I mean, this machine, when they were new, was $2 million. Then it was $250,000. Then they were $25,000. Now you can get home versions of this that are $1,500, or $1,000."