Re: URGENT! 2.92-3.45 Speedo Difference
this is probably a bit late, but something you can do when you get home.
Ford use colour coded speedo drive, and driven gears.
What you need to do, is remove the speedo sender, shine a light in the box and note the colour of the drive gear.
Then go into a ford parts dealer, with the drive gear colour, diff ratio, rim size and tyre profile. They normally can supply over the counter.
Also get a spare clip, sometimes they break when changing the driven gear.
all for less than $5.00....cheaper than a speedo-calibration