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...
Truck was built for the sema show in 2018. We had it on the track with optima,but it only had 15miles on it then. I have been slowly working the bugs out of it since, between customer builds. Want it to be a monster when needed but still have the gearing to hit the highway at a decent rpm.