What is (are) the salient dimension (s) that indicates the Body / Chassis width?
Given that the frame of the body tub sits on the upper flanges of the Z section chassis. I would think it follows that the critical dimension is the distance between the inner vertical faces of the chassis rails. A wider body tub would also require the chassis rails to be more widely spaced to suit.
I don't know what this is on the later/wider cars, but I do know that this dimension on a 1980's era 4/4 is 36".
