What year was the "closest finish in the history of the Indy 500"?

Question

What year was the "closest finish in the history of the Indy 500"?

Answer 1

1982. Gordon Johncock won by .16 seconds over Rick Mears.

Answer 2

No, 1992.  Al Unser Jr. over Scott Goodyear by .043 seconds.

Answer 3

This question belongs in the Indy Racing League (IRL) category....but nonetheless...

The Top 5 closest Indy 500 finishes...

(not including races that finish under caution)

5) 0.570 sec  = 1997 Arie Luyendyk  d.  Scott Goodyear  

4) 0.299 sec  = 2003 Gil deFerran  d.  Helio Castroneves

3) 0.160 sec  = 1982 Gordon Johncock  d.  Rick Mears

2) 0.0635 sec= 2006 Sam Hornish, Jr  d.  Marco Andretti

1) 0.043  sec = 1992 Al Unser, Jr  d.  Scott Goodyear

An interesting sidenote about #1 is that the unofficial margin of victory was actually 0.0331 due to the fact that the electronic timing devices on both cars were not in the same place.  Al Jr's was in the nose of the car, while Goodyear's was in his sidepod.  This would make the margin of victory longer than it actually was, had Goodyear's timing device been in the same position in the nose of the car as Unser's.