Speedo gear 1970 A904 selection

Mike Correll said

I did the math for your tire diameter, and it came out at about 27.0 inches. I used a chart on drivinithome.com, and it only shows diameters of 26.8 and 27.4. The value 26.8 technically is closer to 27.0 than 27.4... if you were to go by that you'd want a 32 tooth and a 35 tooth.

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But I think either way it'd be pretty close... I went by drivinithome.com's chart for my 66 Barracuda with 3.23 gears. With my math, my tire diameter came out to 25.6. That diameter and ratio called for a 33 tooth speedometer gear, so that's what I put in. Turned out really accurate.