Are switching speedo gears the only reliable way to adjust an inaccurate speedo?
I used the calculator chart above to get an estimate of 27 teeth I should need with 225/70-14 tires and a 2.76 rear diff ratio..
I'm coming up with 6.2" sidewalls, plus 14" rims = 26.4" tire diam.
With a 2.76 diff, the result is 27 teeth for the speedo gear.. is that how it works?
The speedo in our '65 with cable-shift 727 automatic is indicating about 10% too fast (reads 90mph when actual is more like 80).
I'll pull the current gear and compare number of teeth in the car..
Thanks,
- Art
Last edited by 67SATisfaction; 06/30/19 02:44 PM.
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