Gentlemen, start your engines! This race-used piston from the 1981 Indianapolis 500 was fired by Bobby Unser, whose #3 Norton Spirit car was used to win the race. That victory landed the racing legend in some pretty elite company, as he became just the fifth driver to win the Indy 500 at least three times (the list is now twice as long). Only Rick Mears has won it more often (four). Signed by Unser himself, the lot also includes a signed LOA by Unser on his personal letterhead. Also comes with PSA certification for each signature.