In California, when a vehicle goes unregistered (not ticketed, and off the radar) for 10 years, or so, it's dropped from their computer databases. At that point, when registering the vehicle, the VIN number is only visually confirmed, and not checked for validity against anything historical. This means, IF you forge/alter the title document, prior registration sheet, dash VIN plate (which they reprint) and the door VIN sticker (also available reproduction) then the engine letter in the VIN can be altered from a G to, for example, an R, then the vehicle is registered as such, nice and legal. Not easy to do, but it can be done. Pour a few beers into a guy I once knew, and he'd tell you all about it.
