my 1959 F-100 came with a 223 6 cylinder and 3 speed The tag on the rear axle is missing. do any of you know what the gear ratio is

 

Most likely 3.71.

 

my truck has the gear ratio stamped on the plate inside the drivers door. im not sure if yours would be the same.

 

Check the rating plate on the inside of the glove box door and then look for the numeric code for the axle This code will tell you what ratio you have. It will be a 3.70/code 01 or 3.89/code 02 or 4.11/code 03 ratio.

If the axle is a 9 inch Ford--you have an open differential. If the axle is a Spicer 44--then it has the factory limited slip differential.