Thanks for the advice fellas.
There are a lot of major mods with this swap. That's why you don't hear about it much, and why you can pick those torque monger 8.1's up for so cheap.
Sooner or later a turned up cummins is going in the truck, but right now a tuned up vortec is my answer.
I figure I can get at least 600 pounds of torque with it, and that will work for now.....
454!!!!! Regardless, your gonna need a big tank. Father inlaw has a 6.0 in his 2009 did what he could to save gas but on a cold day he might get 10mpg. When pulling his tractor or hay bails he might get 7mpg going with the wind. If your trying to save gas by a Honda civic. If you want to put a new motor in a old truck in less then two weeks, I would go with the carb job. Getting all your fuel injection wires, sensors, computer right it's gonna take little bit longer then two weeks, if you do it right. That's all I was saying.
Also, automatic or standard? Rearend gears? Get em right and you can see the 15+mpg with a 454