cant smoke the skins...problem??

it sounds like you've about covered everything.
finish tweeking the carb and timing and if your still
are not happy, more stall or gear or both.
you can either raise your r's to work with your
present cam or drop some cam out to work
with your gearing.
i myself would raise the stall to get into a useful
rpm range and launch if i had to have that cam.
i don't find much over 4.10 gears to be useful in a
street car and 3.91's are a really good gear for all
around driving.
hope you can find your sweet spot
longarm