[Hammered]

Thanks for the quick response. Track width is the distance from the middle of one tire to the other and if the wheels have zero offset, then that measurement would equal the hub-to-hub distance. As you say, the GP frames don't position the wheels out any further and all else being equal, it seems the difference would be in the wheels. A wider wheel alone would not change the track width unless the offset was different. I have see offsets of 1/4" and 1/2" reported for factory rally wheels, but don't know which direction the offset is in. Even so, I don't see how Pontiac could achieve a 3" wider track with only wheels.