AdjustTiming & 3.73 Gears install

[Rally]

Hey Blue01GT, do you ever come up to the Bay Area? There is a great place up hear that is highly recommended that will do the install for $220. I am sure, however, that in the greater LA area there MUST be someone who will do rearend work reasonably.

You have two options for correcting your speedo after the switch. First is a little plastic speedo gear. For a 3.73 gear switch you would need a 23 tooth one. The problem with these are they aren't that accurate, (pretty good up towards 70mph, then off about 5mph or so) and they get ground up pretty bad and will need to be switched. The reason for this is that the drive and driven gears for the speedo don't actually mate correctly (with the 23 tooth) so under the wear of driving, the softer speedo gear gets ground up. Some people claim that they have no problems with the speedo gear, others despise them.

Your second choice is either a mechanical or electronic speedo compensator. These devices (like the Steeda one) work inline and compensate for the change in the gearing (and potential wheel size changes too) and send corrected numbers to the speedometer. Abbott makes an electronic device, and it sells for about $150, although I am sure you could catch a bargain somewhere. The mechanical speedo compensators (SpeedCal) are also devices that work inline, but is used by those of us with pre-99 stangs that have pure mechanical speedometers. These guys would still work on your ride, and they are priced at $79-99. Brothers has one for $79, Dallas Mustang has one for $99. If you search the archives, you will probable turn up volumes on this question, as well as links.

Good luck!