Hi guys,
I'm looking at swaping out the 85 MPH speedo on my T/A. It has the perf. sus., sound, etc. and I'm not sure if that makes the gauges any different. A friend of mine re-painted and calibrated his to go up to 120 (I'm not sure how he did it) but I'm looking at getting one that goes to 140, since that is what seems to be the speed on the newer (after '85?) T/A's. What would I need to do this? I've searched for this topic a lot (horray!) and what I've come up with is that it's a dirrect bolt in, no VSS mods or anything needed. Is this correct? What year range speedometer would I want, and what models? I'm guessing a Camaro speedo wouldn't work? Also, in the years to come (read: when I have the money ) I'd like to swap in a T56. Would the speedo swap mess anything up?

Thanks for all the help.

 

Any Firebird speedo that came from a cluster with gauges from 86-92 is electrically driven; your 85 will/should be cable driven.
It's not quite a bolt-in...you'll need to swap the sending unit on the trans, and do some wiring.

 

I installed an electric 140mph spdo in my car. It's alot of work. The clusters are wired different. I cut and spliced the flex board on the back of the cluster to get the singals comming in to the correct location on the cluster. I then added a buffer box and a Dakota Digital box to correct the VSS signal. I had swapped from an auto to a T5 and I did not know what gear I had in the tail shaft. If you get the correct gear for the VSS you won't need the Dakota box. You will also need to connect the buffer box to the ECM. If your just thinking of changing the spdo and not the whole cluster, they are mounted completly different in the cluster. I did this first and then ended up just changing the whole cluster.

 

So the 140mph speedo is a different size? I was thinking that they were the same size and I could just put it in where the old one came out. Bummer.