You didnt post much about your current 440 other then it being mild and a low compression engine.
For starters there is no reason you shouldnt be where you want to be currently with some very cheapo additions. You were there with the 3.91's already. Yet, we do not know what your application is regarding type of car stock wheel/tire combo etc.
The 500" build can get rather extreme meaning your going to have a new engine and all this new found torque and HP. That in turn may require suspension changes etc. as in fuel requirements and just think it out. Daily driver or weekend warrior. Its just not the engine its the whole car
that has to adapt.
My 65 B-body has a 500" that is somewhat antiquated and im running a host of other goodies and can easlily break into 11's without really trying as I am sure many others can share here.
With the newest technology out there, you can be in the hi 10 sec range without much effort, just $$$ will make the combo work... Give us more info on your set up and im sure you will be happy with what you hear from your friends here.