Does anybody know how many revolutions of the speedometer it takes to clock one mile on a factory 85 or 120 mph speedo? I need this to calculate the speedometer gears to calibrate my speedometer. Thanks -Matt

You won't calculate it that way you need your rear end gear ratio, tire size etc. Go to www.tbichips.com and their is a link to a speedo calibrations. and gears needed to correct. They also sell what you need at good prices.

There are gears in the tailshaft of the trans that control the speedometer. It is a mechanical speedo, not electric. The formulas I found need tire size, rear gear ratio, and speedo revs for one mile. Thanks -Matt

Does anybody know how many revolutions of the speedometer it takes to clock one mile on a factory 85 or 120 mph speedo?
Both speedometers need 1000 RPM to display 60 MPH. Do the math.

http://www.transmissioncenter.net/speedometer_calibration_______va.htm Here is the link you need. Answer to any speedo gear even the electronic ones.
Dan.

Thank you guys for all the help! It helped out a lot! Thanks again! -Matt