I have switched to 18" rims and a 35 series tires and was curious for opinions on what tooth number gear I should switch out to for my speedometer to be more accurate. I am running 3.37's and a Turbo 400.

This should help you out!!

http://www.tciauto.com/Products/TechInfo/speedo_gears.asp

# Drive Teeth X Axle Ratio X Tire Rev. per Mile= # Driven Teeth1001

So what is the difference between drive teeth and driven teeth?