Speedo Gear Calculation

[Mastodon08]

Hey guys, I actually have two projects going where I need to find out the correct speedo gear for the transmissions. I found these calculators online that help figure out the right gear using the tire height, driven gear tooth count, and rear axle ration. My question is what is the driven gear? Is that the input shaft or output shaft or...what is it?

Thank you

[Nacho-RT74]

is located at output tranny shaft to make spin the speedo at the correct rate once you get the wheel size and how much distance represents that into the distance per output shaft turn.

I hope that responds the question ?

[XH29N0G]

I agree, the number of teeth on the gear inside the transmission that the speedometer pinion gear meshes into.

If it is a stock transmission, you might be able to use something like this http://www.mymopar.com/speedometer.htm

[John_Kunkel]

The speedo drive gear on the '66-later autos and 4-speeds is 13 teeth.