Otherwise stated -- the 89 is a direct bolt-in. You can even swap the whole cluster which is even easier. With a 90+ you will need to modify some things.
Otherwise stated -- the 89 is a direct bolt-in. You can even swap the whole cluster which is even easier. With a 90+ you will need to modify some things.
Yes, the wiring is all different so the gauge clusters are not a direct swap. But you can swap the 140 speedo into the older cluster, but that either requires using white face gauges and swapping only the mechanical part while using the plastic face part of the 85 MPH speedo with the new 140 gauge face, or cutting and trimming the 140 speedo face to make it fit into the older cluster. It can be done, but it takes some work.
Do a search on speedometer and you should find several threads on the swap.