Shifting into 3 at 3000 rpms how to adjust

Hello
I didn’t set this up as I bought the car with the work done. It’s a 383/727 with Lokar kick down. I know it has a 3000 stall converter and a trans go pack I believe. I’m trying to figure out how to make an adjustment to shift into third gear sooner. It wont shift into third until about 3000 rpm and 40 miles an hour approx..
I’m not sure if adjusting the kick down would help this problem or has nothing to do with this?

View attachment 1715167834
Forget to mention 68 dart with 68 motor and 68 trans