Downshifting
It does not matter what gear you are in when you 'peg it', what matters is the mph. If you are going 20-30mph and mash it the car will kick down into 1st and give you a real good kick in the ***. For second gear you need to be going at least 50 when you floor it to get a good jump. Our cars have a dead spot from about 35 up to 50. When you floor it in that range, the car drops into 2nd but the rpms are too low for you to be in the power band. Just takes some time and experience and you will know your car inside and out, not to mention how to get the best performance out of her.
Or, as onebadblackz said, get a manual valve body. Something like a TH400 would be cheaper and more reliable than a built 4L60E. (yes I have a built 4l60e, haha)
btw, a stall will pretty much get rid of the dead spots.
A Torque Converter should compliment your heads/cam as well how your transmission is built.
What HP are you shooting for on the dyno?
What quarter mile time are you shooting for?
There are all sorts of things that go into account to pick the "right" stall speed. Then there is also the question of what STR you want on the torque converter...
There's a lot of reading to do on the subject, however it's much quicker to ask someone who builds/sells verters.
Even the weight of the car plays a factor in selecting the appropriate torque converter for your application.

