I need help , my dad wants to upgrade his 89 f250 to a lower set of gears but he needs to know what he has already. The tag reads 2 v126c 3 55 10 2 9a16 I know it's a 250 but Ford heads are Ford heads
Thanks for any help.

 

Here's where I got my gears. The chart shows what's available for Fords. My tag said 975 on it after the 331 gear ratio, but maybe that 10 2 on yours is the 10.25?

http://www.ring-pinion.com/a-ford.html

 

Your diff. is a 10.25" corporate, Sterling axle. It can be re-ratioed to 3.73 or 4.10. Can't remember if 10.25" offers a 4.56 ratio.
Your diff. appears to have been manufactured on 1/16/89.

When purchasing parts (such as ring & pinion), You have the earlier style, or shorter pinion. Pinion in 1992 & later is longer & requires taller (different) yoke.

You may want to purchase a diff. master overhaul kit when changing ratio. master kit would include all bearing for R/P & diff. side brg's., new pinion nut, pinion seal & crush sleeve. Master kit should also include a pinion shim kit & diff. side brg. kit.
good luck, gearman
Your present diff. was built with 3.55 ratio.

 

is that why you're call "gear man X"?

 

x17 is Ford designation for 4 door S/C with syleside, short box.

 

Thanks gearmanx17 and TRK you guys have really helped. I hope some day I can be some help to you two.
Thanks again
duffer57