6.0/4l80 build opinions

[Heavymetl]

Are you insane? Nope.

Turbo wise, for low buck, check out the new On3 7875. The turbine is not so small to choke the 6.0 and should spool quickly.

As for the cam, the LS9 cam will require a front cover change and cam sensor. It's a GEN IV piece. I'd spend a little extra here, as many aftermarket cams are available which are made for a GEN III and work great. Tick, LJMS, Tooley, etc.

Converter is big bucks.
Fuel system is big dollars too. You can't run much boost on pump gas, so you'll need E85 or meth injection in order for the engine to live. Probably do the flywheel 600hp easily but not so much 600 rwhp.

Ditch the 3.73's for something taller. I've got 3.25 in my truck and it works great. Once your in the boost you don't need gears. Torque out the wazoo.

Everything else in your post makes great sense, truck manifolds work great and the LS9 gaskets rock. It's almost as if everything in turbo world is backwards; the engine/turbo is cheap, but everything else cost more. Heck I've got well over $1000 in fuel system alone.