Re: C4 Speedo Gear
look inside your box, see what colour drive gear is fitted, then go into a ford parts dealer armed with the that info, AND your diff ratio, rim size and tyre profile.
They look it up on the computer (used to be the microfiche) and hand you the correct part!!!!
Albeit there are a few combinations that you also need to change the drive gear as well. Ensure you get a clip, they often break....this applies to both the drive and driven gear.
Done this too many times to count.