EJ:

There is a chart in the Ford 1949 to 1959 parts manual, also I have a service bulletin book from CTCI that has a chart.  Those charts may be somewhat inaccurate, because they list combinations with old bias tires.  Radials in equivalent sizes tend to run a little smaller in diameter, throwing the charts off. 

John - "The Hoosier Hurricane"

John, where did you get a chart? I'm suppose to have a 3:78 gear in my '56 but it's 10 mph faster than my GPS and I did some numbers and it sure seems like a 4:10 to me. May have been changed sometime in the past. I don't think it ever had an overdrive in it.

Doing Fords for 45 years. '56 Customline Victoria

E.J. in Havana FL

Your car should have had a 19 tooth gear originally.  You will need a 22 tooth gear according to my chart.  Seems like a big change to me though.  Take your old one along to your Ford dealer and get a 22.  Compare the angle of the teeth on the gear, some "lean" one way, some the other.

John - "The Hoosier Hurricane"

Any idea where to point me for the part, and what gear I would need?

Crab:

Yes, you can change the gear on the cable to do what you want.

John - "The Hoosier Hurricane"

Can the gear be changed from using 3.1 axle to 3.56 to get the speedo calibrated?I need to slow the guage by  15%.