Just bought a 94 GT with 3.90 gears and need to get the speedo calibrated. Anyone know what I need? Is this something I can do myself? Any help is greatly appreciated.

 

Handheld tuner or SpeedCal.

 

I see all speedo gears except one for a 3.90 rear end. I would like to be able to do this myself. Where can I get a Handheld Tuner or SpeedCal and how much do they cost? Where can I get one. Does anyone else out there have a 3.90 rear end that could shed some light on the situation?

 

Didn't read the '94 the first time. Sorry, tuner/speedcal won't work.

2195.55 rpm for 4.10 at 60 mph, which is 63mph with a 3.90 gear. Therefore, a speedo gear for 4.10 gears would read 3 mph fast on your speedo. 1 tooth less should be about right.

What are the tooth numbers for speedo gears for the 4.10 and 3.73 gears, anyway?