Looking for gear changer near St. louis

[slowmotion]

I have a ford 9in in my altered. I need to change the gears for 4.56 to about 3.70. I'm looking for someone in the St. louis area that does that for a reasonable rate.

[sds10racer]

if you have any ability, you should be able to do it your self as this is a simple rear to set up.