<VV> FC pinion shaft gear & odometer

[Daniel Monasterio]

    I am playing with my Rampside's speedometer to make it reading Km instead of miles (have several disassemblied GM speedos) but, as a starting point, I don't remember two things:
    1.- How many turns on the speedometer shaft for each mile ?
    2.- I remember that the drive gear pressed on the diff's pinion shaft has multiple threading but, don't remember if 3, 4 or 5 threads. 
    This is for doing the necesary math in choosing gears.

    As always... thanks in advance for any input.

    Daniel Monasterio