Return to Speedometer Gear Calculator

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© Copyright 1990 - 2014 West Coast Classic Cougar, Inc.

1967 - 1973 Mercury Cougar
(and Ford Mustang)
Speedometer Gear Calculator

Rear End Axle Ratio (ie 3.25, 4.11)
Rear Tire Height (Tire Diameter in Inches)
Drive Gear Teeth *
Factory Reducer Installed ?
None
Reducer for C6 w/ 3.91, 4.11 or 4.30 Rear End
Reducer for 4 Speed Manual w/ 3.91, 4.11 or 4.30 Rear End

Vehicle that were factory equipped with the
3.91, 4.11 or 4.30 rear axles came with Reducers

 

* Common Drive Gear Teeth:

C4, C6, or FMX: 8 Teeth (Some 429 Police Intercepters came with 9 Teeth)
3 Spd: 6, 7 or 8 Teeth (Chart Coming Soon)
4 Spd Toploader: 6 or 7 Teeth (Chart Coming Soon)

© Copyright 1990 - 2014 West Coast Classic Cougar, Inc.