Need help figuring out what speedo gear to order

[cuban11182]

Not sure if this belongs here or not, but I need to figure out which speedo gear I need. My 84 has a "B" stamped on the rear axle and it seems I have the 3.31 gears. The tires I have on are 30x9.5x15. Since I have a cable speedometer I'm assuming that I need a longer shaft gear, but the charts that I see go from a 3.07 to a 3.55. How many teeth should I get?

 

[Jimbos76cj]

I would split the different and run a 31 tooth to see. For what its worth they used the same gear style up into the 90's so If you had the time to hit a YJ and look for jeep vehicles with cable driven speedos you may be able to find what you need.