i have an 86 iroc and was wandering what kind of pain it would be to swap my 145mph speedo for one out of 91-92 IROC-z. i like the way that the odometer looks out of the 90-92 IROCs.

 

90-92 are electric driven (not cable), with a speed sensor in the trans in place of a speedo gear, and it's all tied in with your computer. 89 and older are cable driven. Needless to say, it wouldn't be a simple changeover. You sure you still like the 90-92 style?