Speedometer Gear

Don't you need to go with more teeth? This is the chart I use for the early cars.

Tire Size Tire Diameter 2.93 3.23 3.55 *3.91 **
6.50 x 13 23.2 19 21 19 21 --
7.00 x 13 24.3 19 21 18 -- --
7.00 x 14 25.4 18 20 18 -- --
7.50 x 14 25.9 18 19 21 19 21
8.00 x 14 26.4 17 19 21 18 --
8.50 x 14 26.6 17 19 -- -- --
9.00 x 14 26.8 17 18 -- 18 --
6.70 x 15 26.3 17 19 21 -- --
7.10 x 15 27.4 17 19 -- -- --
7.60 x 15 28.3 17 18 -- -- --
3.55 use .800to 1 ratio adapter 3.91 use .800 to 1 ratio adapter 4.56 use .800 ratio adapter