Did a castor offset bushing installation yesterday with no center to center measurement using this jig, it fits the bushings like a glove. HINT... Important make your plum-bob measurement after the springs and shocks have been installed and height has settled. My ARB bushings were tapered on one end only, Jig could also be user to determine degree of offset with slight modifications. Materials used standard 1/2" copper plumbing pipe (type M thicker wall). You can push one bushing home then install the other. Also noted it is possible to remove and install the rear shocks without removing the 2 bolts holding the shock, this avoids breaking them if their rusty.