This is asked all the time, I'm sure you could find stuff using Search. But I'll help ya out anyway... the cluster isn't an 88-91, it's either 88-89 or 90-91. If yours is the same group as the one you found, it will plug right in and the tach will work. If you have a 90-91 and the cluster is an 88-89 or vice versa, you'd have to swap the plastic housing and do some rewiring to make it fit and work.