Headers & Cam upgrade or Rear Gears

How much of a change would it feel like?
A good bit for sure.
Where to get a new gear?
Here or Year One or the like place. Year one has a table on what gear ratio & tire size combo with what gear is needed.
What would a trans shop charge?
If there good fellas, nothing or maybe a cup of coffee.

The gear is easily changed by yourself with only 1 nut to be removed on the outside of the transmission where the speedometer cable goes in. Remove the bolt, the metal “Y” retainer under it, pull the cable and the whole assembly pops out. Take the gear (on a stick) swap, shove back in, replace retainer and bolt, tighten, your done. The only other thing is to “Clock” the housing to the Corresponding amount of teeth on the gear. It is marked on the outside underneath the white plate. Just clean the grease off and you’ll see the numbers.