I have a 1953 F250 with a 302 4-speed OD transmission. From what I can tell it retains the original rear end but the tires are now 4" shorter then the originals. The question is: Is there a speedometer cable that will work with the original speedometer and how do I calculate which gear to use. Thanks....Steve

 

I used to have that same tranny. Actually the stock cable may work as long as it reaches the hole on the tranny. As far as the gear goes you will need one with less teeth. Figure out how far off you are before throwing gears at it by testing with a GPS or a phone app.

Here is a formula for you.
Speedometer Gear Calculator and Charts - TCI® Auto

 

a speed o cable # is ca3010 it is 83 in long but will fit to a c4 or what ever got it at o Riley

 

As usual...great help from FTE. Thanks guys, I will check it out.