How much work would this be? I was looking on eBay and found some cheaper than buying a new, or having mine calibrated, but they mentioned it needed minor modification to fit 87-89?..
actually i think it's pretty easy. For the life of me i can't remember where but i read a mini-article where someone did it. I'm sure it's possible. If your game i'd say grab it up and then pull your cluster out and see what needs to be done. Hopefully someone can chime in here and tell you what it entails.
no reason to swap over the entire cluster, the actual speedo part pops out and unbolts, and you can swap that into your current cluster. your miles will now be wrong. That can be changed too, but for security reasons, you'll have to figure that out on your own, but just swap over the actual speedo, no the cluster.