So i just completed having a new austrailian posi cone carrier from GM installed along with Yukon 3.73:1 gears into my rear end. I can sure feel the difference even though I am still breaking in the gears.

 

Isn't it great what happens when you can get into the torque curve faster? I went from 2.73 to 4.11 gears when I swapped to the Ford 9" rear. I was barely able to do a one wheel wonder and then could light up both tires and put the car sideways.