I pulled a 140 MPH speedometer out of a Trans Am and want to replace my stock 85 MPH speedometer in my '87 firebird with it. What do i have to do outside of removing the stock gauge cluster and installing putting in the new guages? Need to know if the calibration is different and if there anyother parts i need (i can go back and pull them out of that same TA as well).

 

The calibration should be the same.

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1989 IROC-Z 5.7L
NOS 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

 

As you can see, I have been using the search function... I am having new car fever REALLY bad and have been looking at Firebirds and Trans-Am's the past few days. There is a local 87 Trans-Am I am considering making an offer on, but it does have the dreaded 85 MPH speedo in it. I definately want at least a 120MPH speedo in it, preferably the 140. I just want to verify what I have been reading from the threads I have found.

All 86 and newer Firebirds and Trans-Am's have the electronic speedo.

The clusters should just be "plug and play" because the electonics within the speedo will show the proper calibration. Is this dependant on the rear-end of the car though??

Thanks for any help on this matter. As stupid as this sounds, the ability to EASILY swap the guage cluster to a 120/140 MPH speedo impacts my decision alot on considering this Trans Am.

Thanks!!

 

The speedometer gears in the transmission will make your speedometer read correct if they are for the correct rear axle. The speedometer itself is independent of that.

The vehicle speed signal is picked off of the speedometer gears and output through the v.s.s. sensor. The ecm receives the vss signal from that sensor, translates it, and outputs it to the speedometer.

Buy that trans am, gauge swapping is easy in these cars

 

Exelent thread, i am just about ready to replace my 85 mph speedo with the 145 and was wondering the same thing

 

I think it is the same for camaros, electronic ones anyway - 91-92 camaros, mechanical ones for 82-90 camaros - dont know.

 

make that fuzz buster modification to your dash while you are at it

I have a v-6 firebird car that came with a 120. I replaced it with a 140 and It worked great

 

It's been sold already.

Oh well, I'm still going to keep it in mind when I am looking around.

Thanks everyone for the information.