[Tdrcreyn4]

I have a 1969 K20 with a 396, NP205, TH400. It has a 4" lift and I run 35's. It is not a garage queen and I use this truck and like the power and durability of what I have. I am now getting to a point where I want it more streetable without sacrificing the performance I have now. I was considering adding a gear vendors Over/Under Drive to the truck but now I am wondering if I might just be better off with a modern 4x4 transmission with overdrive. I want something that is tough and will stand up to off road but still allow me to take a long road trip without breaking the bank on fuel.

What advice do you have for me on this? I want something that can stand up to 450 - 500 HP and the torque requirements. What transmission/what do I need to convert over, etc. All opinions welcome and thanks in advance.