Just a quick question. Will the gauge cluster from a 87 Trans am fit and work in a 92 Formula? they both look the same , Want the 140 mph.speedometer . Thank's

 

Firebirds went to an electronic speedometer in '85 so any cluster after that should work. That being said as long as your car came with the full gauge pack (Tach, oil, Volts. etc.), and not dummy lights it should be a straight forward swap.

 

Looks can be deceiving ....

I know for fact the 1987 used a separate "VSS buffer" (Vehicle Speed Sensor) whereas the 1992 had it's VSS connected directly to the ECM with no external VSS buffer .

Will it work ? I'm honestly not sure , If it does , Great ! you'll have the speedo you want . If it doesn't work , it'll likely be the difference in the VSS buffer setup that will be the pitfall . Something about different "PPM" (Pulses Per Mile) in the two setups sounds familiar , like the early one could be 2000PPM whereas the other , later one might be 4000PPM but my memory ain't all that clear .

 

Here are the 1987 and 1992 wiring diagrams showing the 1987's use of an external VSS buffer VS the 1992's use of a VSS buffer internal to the ECM ...

 

I'll just swap them out and see what happen's. I will post the result's when done. THANK'S for the help