I was also wondering on clutch options, I have a few more parts in the mail and was figuring on needing a clutch.

 

I have a 2004 silverado 4.8 5 speed 4wd and I'm wanting boost idk what years the nv4500 is compatible or what I'll need for the change. Do I need the 4500 transfer case?

 

the nv3500's np241 transfer case should bolt right on - just verify yours is 32spline input. flip the stock crossmember around (driver's to passenger's side). swap to nv4500 reverse switch.
as for the trans, the wikipedia page actually has a decent breakdown of what year transmissions had what gearing & (i think) clutch setups... early models used an external slave. one thing i also learned when swapping mine is the nv3500 slave & flywheel cross-referenced as the same part numbers for the nv4500 (depending on the year of the equivalent setup: 99-00 NBS, 01~04, and ~05+).
you'll want the 95-00 GM transmission lid regardless of the trans year (which i believe you want the 96+ GM trans), as the slightly shorter lid fits into the non-body-lifted trans tunnel a little bit easier.

 

also, unless you're loading it up & running fast/heavy in OD, you'll probably prefer the gearing of the nv3500 better.
even the Joe Gibbs guys left the stock nv3500 in the blown 4.8 trucks with the factory warranty.

it completely made my 4.30s useless now, & i drive it as a 4speed. so i'm most likely going back to the stock 3.73s sitting in the garage because to even get close to an equivalent of the original usable 1st gear, i'd almost need a 3.08. potentially considering trading for 3.42s... we'll see.

 

I've heard they wont take 600 hp I had the 4500 in my dodge and it took 750 and i beat it to death never had an issue

 

fair enough. my t56 is putting down almost 700 to the wheels in my car, and i've seen its longitudinally-mounted equivalent crap out with less than half that power swapped into a suburban or ECSB trying to pull a trailer.
all in how it's used - that's all i'm getting at.

 

Zebra is right we both killed our NV3500s by towing in overdrive at high speeds with a heavy load for a long time. Other than that I had no major issues with mine besides that it was noisy and it occasionally didn't like high rpm 2-3 bang shifts. Another member in here had a turbo 8.1l big block mated to an nv3500 and he beat it regularly without failure.

Not saying dont do it because I like the piece of mind that I can tow and do whatever I want with the nv4500. But I would think about what your goals are for the truck.