[bandit37388]

Lot more than just that needed for it to be correct. Have to take into account tire size also. And do lots of math.

1. First determine the Circumference of tire in inches.
2. Second divide that into 63360 (number of inches in a mile). This tells how many revolutions your tire makes in 1 mile.
3. Third multiply that by your rear axle ratio. This determines how many revolutions your drive shaft makes in 1 mile.

4. Finally find a ratio of availabe drive and driven gears that will cause your speedometer cable to turn 1000 revolutions per mile.

If you need any more help with this feel free to pm me. I used to have a spreadsheet I created for doing this. Can't seem to find it right now, but can certainly recreate if needed.

Steve