I bought a complete 140mph/8K RPM tach cluster on eBay. I'm going to use it to replace my current 120mph/6K RPM cluster that is in my 92 GTA.

Here's my problem; I just removed my 120 cluster and on the label attached to the bottom of the fixture is say "8CYL", good so far right. Well the cluster I got off of eBay says "6CYL" on the bottom What gives????? Will it still work? Here is exactly what they say:

140mph/8K RPM Cluster Label:

ZGB
25081623
257400-0230
6CYL LB-8

120mph/6K RPM Cluster Label:

ZCA
05089620
8CYL
257500-5490


Will the 140 cluster still work just fine in my GTA????? I mean correct me if I'm wrong, but wasn't the only V6 to get a 140 speedo the 89 TTA and this one isn't from a TTA! Did someone simply swap the face of the speedo and tach? Can I just put my tach in the 140 cluster? Is this the correct cluster after all?? What do I do?????

Thanks!

 

Well I finally got it all working correctly. It turns out that the new cluster was a pre 1990 anyway that was missing the airbag idiot light. I went ahead and simply removed the 140 speedo and 8K tach from it's housing and put them in my 120 housing after swapping the odometer to that my milage is correct. Now everything seems to be working just fine although I haven't driven it yet to confirm the speedo works.

Anyway I have 1 final problem. Looking at the new cluster, the needle for the speedometer is a lighter shade of orange than the other guages and it bugs the hell out me now.

Is it possible to swap the needles on the speedos? How do you do that?

Thanks!

 

The difference between the 8K V6 tach, and the 8K V8 Tach is simple...
How it works is each time a cylendar fires it sends a pulse to the tach, IF you have a V6 tach in a V8 car when you are run 3000 RPM you will indicate 4000 RPM....

IF you swapped out the board, and the Speedo itself then you should not have a misreading.

John

 

It turned out that the tach was for a V8 car afterall, it said so on the bottom of the face of the tach.

I used a fork to remove the needle and swap them and it turns out it reads EXACTLY as it did before, talk about lucky!

Another project finished

 

I thought it would extreemely odd to have a 140 MPH Speedo on a V6 car... Since it was never available from the factory... Matter of fact, no base Firebird ever got the 140 Speedo according to the PArts & Illustration Manuals...

John

 

Think about this. A Turbo TA would have an 8K tach and a 140MPH spedometer. Also it would be pre-1990.

 

i tried to put a speedo from a 87 GTA (140mph) into my 90 Formula (that had a 120mph) and i couldn't get the speedo to work,i just haven't gotten around to messin' with it latley.

 

I went from a 92 GTA to my 87 Formula, so I know there interchangable going backwards...


What I did was actually swapped the speedos, and the controller board from the IP...

John