190 kph to 140 mph

[d.r.moss]

So I'm a new guy to the forum, had my mustang since 2001, and I dont think I will ever be done with it. It is a 1988 GT 'canadian car'. It had a 190kph speedo in and I swapped it for a 140 mph. It still reads like it has the other speedo. I believe I need to get it recalibrated but how do I go about doing this. Also, I have the stock speedo gear in the tranny but I have switched my gears to 3.55 and thinking about 3.73. I have 18x9 in back with 285/35/18 NT555R. Can anybody help me out as to what speedo gear I need to get, or how to calculate it and where to get one from. Thanks for any advise. I'm gonna post some pics of the car as soon as I find some good ones

 

[d.r.moss]

Anybody???

 

[Mustang5L5]

There is no need to change the speedo gear in the tranny.

All the calibration is in the actually speedometer itself. So when you swapped to a 140MPH unit, that should be all you needed.

What did you swap exactly? The gauge face only? Or did you swap the "guts" behind the face too?

 

[d.r.moss]

I swapped the guts and everything. I got the 140 speedo from a guy that builds cobra kit cars, it was on one of his donor cars. He told me I should only need to put it in, but when I'm going 55mph, the speedo shows around 75mph. I thought there may have been an issue because I was going from kph to mph?

 

[Mustang5L5]

Sounds like one of his doner cars had an 85MPH speedo that someone put a 140MPH face on top of. Do you have a part number off the speedo face?

 

[d.r.moss]

I can get it later, do you have the part#s I can compare it to until then. I will be p****d if thats the case. Whats the point of putting on a different face?

 

[Mustang5L5]

I have an 85MPH speedo here

The only p/n on the actual guts i can see is on the gold shell over the odometer.

It's E27F17300CA and then the date 11 / 1987

This came out of my 1988 LX which was built in Jan 1988.



WHy would someone do that? trust me it's been done. There have been posts where guys slap a 140MPH face on and then say "Okay, what speedo gear do i need to recalibrate it for the 140MPH face" Actually, i think you asked the same thing sort of

The calibration is in the guts. Not everyone knows this

 

[d.r.moss]

Thanks for the advice. I'll look into it once I get a chance. Is there a fix for this or do I need to get another speedo.

 

[Mustang5L5]

You can send it out for recalibrating or it might be easier/cheaper to find another