i'd be looking at a 6.0L over the 5.7 personally.

6.0L
LS6 heads
Rossler Trans
4.10 gear
Detroit locker
3000 Vigilante

 

If you wanted n20 ad enough just get the NX intercooler setup. Im not saying 4l65e wouldnt work but if I was to do that setup I would spend the extra $ and do the 4l80e and be done with it!

 

the nx intercooler set up wouldn't do a whole lot on an air to water set up. you would get a lot more out of it by just spraying it into the motor.

 

Zippy - A 6.0 would be cheaper, but a LS6 weighs a little less, ~80lbs is what I have heard. But a 6.0 would be stronger.

As far as the 4L80e, how much harder is it to swap? Cost diff? Powerloss through drive train? < should I start a new post?

 

Difference between the two would be 65lbs. The 6.0 block would be stronger, but you could put a stock LQ4 with upgraded studs and bolts, and run on that truck all day. It would be a bit cheaper too. Both would be good choices.