For anyone out there wondering the WMS(wheel mounting surface to wheel mounting surface......i.e. axle width) on our Corp. 12 bolt is, it's 63"(that's what I measured). For those of you that know what this entails, this should be a little gem of information that you can now find in the search for future use. I looked earlier and couldn't find it. As for the front, who knows? Mine has a 4.5" lift, so the A-arms have brought the front stance in substantially as the height increased. I assume Isuzu would have them the same, but I really don't know.