Turbo 400 Speedometer Gear Chart, The speedometer is running 10 MPH higher when running at 70 MPH (80 on speedometer). These charts should help you narrow down the selection of the proper gear combination to use in the transmission and speedo cable to 'get you legal' Cutlass - Transmission Speedometer Drive Gear Help - I recently bought a 1970 Cutlass Supreme with a factory 350 motor and factory 3 speed automatic transmission. Was wondering if there is a chart to know which color gear I need since it's kinda hard to use the calculator without dropping the tailshaft off my daily? Calculator Instructions This calculator provides the necessary information needed in order to determine what transmission speedometer gear is needed in order to properly calibrate a speedometer. The person that had it before put 15 inch Craiger SS wheels with. Speedometer gear usage 1967 Tempest & GTO INFORMATION SUPPLIED BY George Pearson Speedometer gear usage 1966 Pontiac (All models) Information supplied by George Pearson Aug 15, 2022 · Set That Speedo! Getting back up to speed Gear changes, transmission swaps and tire sizes. This is very useful when there is no established baseline from which to work from such as replacing a transmission in a vehicle that was purchased without a drive line! While typing these pages, I realized there are literally thousands of combinations of speedometer gears. All these changes can cause problems with accurate speedometer readings. Calculate the tooth count of the driven gear for different transmissions and speedometer gears. Aug 23, 2024 · There is a chart near the bottom of the link below that shows the color vs # of drive teeth for the turbo 400 then go to the calculator at the link below, scroll to the top of the page and key THAT number into the first box (# of drive teeth) Speedometer gear usage 1970 Lemans & GTO iNFORMATION SUPPLIED BY George Pearson Hopefully you will find the layout and how the data are presented acceptable. (About 10ish mph) My TH400 has an electric speedo instead of a cable. rf, rbysao, pxv, pwvc, rzdusb, 1yssxe, lfbyr3, i4ow, uz5qtr, ldio,