How do I make my motor down shift?

I have a 1980 Chev shortbox, 2 wheel drive, rebuilt motor and new tranny, but i didn't rebuild it.  I was looking under the hood and found an after market throttle cable bracket, it was bent to make it fit in.  I finally started to notice that my engine isn't shifting down when i punch it, it just stays in the 3rd gear and i get no power.  i've been messing around with the bracket and got the shifter and throttle cables going straight instead of bent but i got no acceleration.  any tips on how to set up your shift cable so it will downshift and get more acceleration when i hammer the pedel down?  It's a 350 chev, with a 350 turbo tranny and a quadra-jet carb.  

Make sure at WOT(wide open throttle) that the kick down cable that attaches to the carb from the tranny is almost fully extended. You need to be careful to make sure that the kick down cable from the tranny isn't getting over extended. If need to, you can make an attachment for the cable to get it to adjust properly,if you already do not have the correct attachment for the kick down cable. If you get the adjustment right, it should down shift for you no problem. It just sounds like an adjustment problem, based on the fact that you had to straighten out the bracket. Hope this helps and good luck.--Phil

the t 350 has 2 things that makes the box k/down

1 is engine vac from 0 - 35 miles

2 is the k/down cable 35 up

<1> has to have constant vac form intake.   do not have a big hole feeding the trany because it will k/d 2 easy

<2> k/down is happens just on full/t

I know iam a LOT late but, check out bowtie overdrives web site.  they describe the TV cable adjustment very well.  

First engines (motors) don't shift "down". Transmissions shift "down".

Motors get their power from a outside source, heater fan motor,etc.

Engines create power.

That should bring some comments.

Patrick