Ring/Pinion swap-speedo ???

[locknut]

Did a R/P swap on my '02 2dr Sport 4X2 from the 3.73's to 3.27's for better gas mileage.The tech says nothing in the computer for this gear,and the tire size available in the computer is minimal help to make the speedo accurate.
Any other ideas out there???

If my calcs are right,the speedo needs to read about 13% faster.

 

[Cobraguy]

If Ford can't calibrate it with their software, you may need to see if James can with is. Henson Performance. He's a vendor here.