Thanks for all the info everyone, it has really helped point me in the right direction. I've decided to remove the 3.55's and install the 3.23's.
And I'm gonna remove the 9.5" Dynamic street/strip converter and get me a heavy duty 11"(maybe a Hughes?). I think that combo will make me plenty happy and will save the tons of money it would take me to buy an overdrive setup.
My MP 557 cam is very smooth even right off idle so if I can cruise down the highway at less than 2500 RPM's I'll be all set.