Kickdown problems

There should be an adjustment at the bottom of the linkage underneath... You need to adjust it so it is bottomed out on the trans at wide open throttle... Get a helper to press the gas pedal while you go under and check the adjustment...

Also your vacuum nipple for the power brake port is open... You should put the hose on for the power brakes or block it off with a cap, otherwise you will have a large vacuum leak and it will run rough...