440 what am I missing here?

What the OP does now really depends on how he intends on using it. I am inclined to believe this is a lot more cruiser and driver than a street and strip deal. While a converter tuned to the vehicle would be optimum regardless of the performance level, I think maybe a cam and intake that more closely matches the existing converter would probably suit the intended usage of the vehicle better than to have it really not reaching potential until a set of 4.10 or deeper gears are installed. But everything else concerning tuning needs to be done, too. But that's completely up to the OP. That truck is so nice, I would park it in my living room with mirrors under it so I could just sit and look at it...