Speed Cal help!!!!

[scca_stang]

So, I installed my IRS today and thus my gear ratio changed from 4.10 to 3.55.

stock gear in my car was a 2.73

Car is a 95 GT BTW....

The problem is that the speed cal that is in my car, was there when I bought it, so I have no idea what brand it is (cause it is not marked in any way) All I know is that it has two banks of Dip switches and the Board is Marked with GMM inc. I attempted to look it up online with no luck, I also found a number on the board and attempted to search it too and found nothing...

so the next step I took was I looked up a speed cal on American Muscle (instructions) and the instructions for the DM speedo didn't line up, so I know it's not a DM...

please help, I definitely need this fixed so I can know my speed.

Click to read more...

 

[01bluesnake]

the only thing i can think of is take it on the highway, find a rpm with those gears that the speed is known, and play with the cal till mph and rpm are correct for that gear.

 

[Bob_Kurgan]

grab a GPS and keep flipping switches til it works