Hey I have a 1991 Camaro RS with the 110 mph speedometer I heard somthing about all I have to do is get the Z28 145 mph speedometer and it will show the correct speed above 110mph because I heard it's an electric speedometer. Yes my speed limiter has been removed and my camaro isn't stock so I have no problem with the 115mph speed limiter and I can do way above. Please e-mail me if you know anything about this dmxrules24@aol.com

 

I don't know about the 91, but the 83 145 mph speedometer is cable driven and is a straight swap for the old unit. If you have cable now, it should work OK.
if the speed reads wrong it is easy to fix that by getting a different speedo drive. You get a new gear and housing, just undo the 10mm bolt and change it out. The grear inside the transmission stays the same, but the one that connects to the speedo cable and it's bearing house change (must get them as a matched pair).
I found the Chevy dealer sold the real thing for around $50, but a transmission specialist wanted $110???

 

Being a '91, it is electronically driven. I'm not sure if you can simply swap the 145mph in there or not. I would think that you would be able to, and would guess that the read out on the speedo is calibrated within. The pulse rate from the transmission is the same regardless on the speedo, which further backs my guess. If for some reason it did not read out correctly, you could always use a SGI-5 and recalibrate the signal. If you would need to do this, make sure you use a signal source going to the speedo AFTER the split to the ecm, other wise the signal going to the ecm will be incorrect(which will effect a few things).

 

The 110 and 145 guage clusters are interchangeable. As long as your drive and driven speedo gears are correct, just swap guage clusters and everything should work fine.

 

thanyou for your replys they werea big help