When I put my 4.10s in, I unknowingly had the wrong code in my speed-cal. So, when I pulled out of the shop my speedo was off pretty bad, it would shoot up to 150mph on the speedo and bounce of the speed limiter when I was really only traveling about 35mph. At 15mph, it wasn't off that much, maybe 20mph.

There's really no way of telling how many miles are really on that Mach.

 

This is correct, On my Mach (A4 auto) the percentage differece from the 3:55 to the 4:10 is a fraction under 20%. so for every 5 miles you travel the odometer will say 6 miles, meaning every 100 miles will put 120 on the odometer, not knowing what the miles were at when he had the 4:10's installed, there is no way of knowing the actually miles now.

Plus yes the faster you go the farther off the speedometer will be, at 10 mph your looking at just under 2mph off, not very noticeable, but at 75 mph your now looking at 15 mph off.

On a side note: I thought the Speed cals did not work for the Machs because of the computer controled speedo, it was my understanding you had to use a hand held tuner or have it dyno tuned to fix the calibration... I guess i heard wrong???

 

Sounds like a hassle...
I might pass it for something newer. Or you could always buy it and rebuild it.

 

humm my old 99 cobra i need new cluster they put the same mileage i had one it , well they couldnt tell what it had on it so i went by tha last car fax mileage than got towed to dealer to program it..

my bro in law did a car fax. last time in shop was 2-06 it had it had 56k on it ? not sure if the speedo was right then?

clean title no wrecks

edit ... one 1 owner i ned to find the org owner.it was a dealer trade in.

 

iam going to pass on it.

wifes wants a vert again. so she stuck with the 99 v6 true blue with black top and bullet wheels , it was white with white top with 15 inches on it . she likes the car like it is , but wants the v-8 sound. and no mac backs dont sound good even with the pace setter dual convserion kit. i rather drop a 99/04 gt motor in it .i got to call mps

 

I use a speed-cal, they'll work on Machs. I wish I had of just bought a handheld though. The cruise control and speedo are so sensitive on our cars, that I had a tough time getting a good enough connection. My cruise and speedo will still jump every once in a blue moon.

 

it probably really does have that many miles the person probably just took off the programer to sell it seperatly

 

cant you all read?

did a car fax. last time in shop was 2-06 it had it had 56k on it