Maybe with the rears wheels fully turned they possibly are. Also, the fenders flare out just a bit so that may be just enough to get it over 80".
-Matt
EDIT: I found this link: http://www.truckworld.com/Truck-Test...silverado.html At the bottom it says the truck's width, 83.5". So there you go. 
Last edited by Beast12; Jan 23, 2006 at 03:17 PM.