OldSub.. I used the same measurements for the for the 3100. You are really measuring ftom the centerline of axle foward to account for the draglink. I made sure the wheel stops prevented rubbing the steering unit,(also the tie rod ends) on hard turns. Just have to mock it up and add space if you have to, wheel backspacing ect. When you weld up the mounting tabs to the frame you have some wiggle room for adjustments ( if you make your own). Really the installation was straight foward, the steering wheel bearing kit for the end of the steering shaft made life easy when preparing for the Boregeson joint. I also welded a support on the steering shaft cover on the inside of the cab to bolt to the firewall. Put it all together and it worked the first time...amazing.
