Sweet thread! I'm doing the same thing right now and can use the tips! 2004.5 LLY, 200,000 miles, Air Dog 165, and built trans in place. EGR deleted and PCV rerouted. LBZ cold air and elbow.
For parts, already have the ARP head studs, extreme engine mounts, Max Flow exhaust manifolds, LB7 up pipes, down pipe and new radiator from the Dmax Store plus a welded water pump, new pulleys, belt and tensioner, and EFI live (removing Banks Super Tuner that has in there since 2005). I think I'll also add a welded y bridge and both intercooler pipes.
Tomorrow I order the Danville 63.5 as its good for 600+ yet is still good for towing (which is the main use of this truck) and will work with them for tunes. Picked up a fish DSP5 off Amazon and looking for a place to install it along with a Merchant Automotive High Idle kit.
Will do the head gaskets and reassemble with the new parts and not planning to touch the shortblock.
Anything else you plan to do that I've missed?
2004.5 Silverado LLY. LBZ mouthpiece, S&B LBZ CAI, LBZ elbow, Banks LB7 monster exhaust, Rancho 4" lift, H2s wheels with 315's. Hammerhead pre-runner bumper. Airdog 165. All LED conversion with halogen projectors.