You can get a built AOD at GER for a good price. try
www.gerperformance.com
Dont use their converter though, it didnt work well for me, and I got a stallion from
www.converter.com they rock.
Get yourself some heads while you are having the motor rebuilt, and a Cobra or Trick Flow street intake manifold are the best value.
The 70mm TB is ok, you will give up some "throttle response", but probably wont affect your performance to much. Then again, on a stock motor like you have now, i guess it could hurt you slightly.
The 86' heads were especialy weak, so that would be a great mod fopr you to make.
I know you said you didnt want to spend much money...but, how fast do you want to go? Speed and horsepower cost money. If you want to go fast, spend the dollars. If you want to dream about going fast, press on like you are doing now.