Speedometer Gear Size 1972 th350

[88gtstreetrod]

I need to replace the bullet and speedometer gear in a TH350 transmission. I can not seem to find what the stock size is (color)? or the size I need for the tire size I am running. Any help is appreciated.

I have seen the calculators and can't use them because i don't know the transmission drive gear ratio.. if you know what a stock transmission gear drive ratio is for a 1972 TH350 is.. that would be great

Truck has the 3.07 rear end and tires are 28 inched tall

Thanks!