Swapping a 140-MPH Speedo for the stock 95-MPH one!
I bought a cluster off eBay because it had a 140mph Speedometer in it. I removed the 140-MPH Speedo and replaced it with my stock Speedometer. Then I took the 140-MPH Speedo and installed in my original 86 TC Cluster (there are some other changes besides the Firm Ride light, but the 87/88 Cluster will work in the 85/86 TC's).
Here are the two Speedometers side by side:
Here is the back-side of the Speedometer looks like (I could not see a differance between the 140-MPH and the 95-MPH)
And here is the Final Product I installed in my 86 TC Cluster: