On an LQ9 Block bored to 4.030 and using 4" stroke to make it a 408, would the Dragonslayer crank and Lunati Pro Billet Connecting Rods be overkill in a boosted application targeting 1000-1200 HP through a TH400? Can I go with Callies Compstar and the K1 Chevy crank instead or are those not good enough for that power level in this application? If not then what should I use? I want the motor to stay together and I have no idea what these internals are rated for. How does the 10:1 CR build below look if a S484 turbo was to be used? Not looking for sponsor feedback along the lines of "we can build you a 408 for $xxxx" as the point of this post is to actually get an understanding of what types of internals are rated for what power level. If test data exists, I'd love to see it.

Pistons - "Wiseco -20cc Dish Forged Piston Set for 4.0"" Stroke, 4.030"" Bore #10-K456X3
Piston Rings - Wiseco 4032GFX - Wiseco GF-Style Piston Ring Sets
Rods Callies Compstar 6.125" H-Beam, ARP 8740 Bolts
Rod Bolts ARP 8740, included with rods
Crankshaft "K1 Chevy LS1 Forged Crank 4.000"" Stroke #10-012FAE400
Main Bearings Clevite H main Bearing Set (MS-2199H)
Connecting Rod Bearings Clevite H rod Bearing Set (CB-663HN)
Cam Bearings Federal Mogul Sealed Power (1898M)
Main Studs ARP 234-5608TFS 225 (61cc) complete from BTRBTR 0.660 titanium springs
ARP 12-Point Head Stud Kit
Morel 5206 linkbar lifters
Comp Cams Trunion Upgrade 13702-Kit
BTR Stage 3 turbo camshaft
ARP 134-1003
OEM LS2 Timing Set
LS9 MLS HEAD GASKET - 12622033 0.055 w/ 4.10 bore dia (L+R)

What intake to use on this setup?

 

Power ratings are a crap shoot. Not every company will use the same principle for power ratings. Some will say "the rods have made 1800 horsepower", others will say "they're rated to 1200 indefinitely".

In all honestly, anything forged is going to withstand 1000 horsepower. Even Chinese forged rods are going to handle more than that (Callie's Compstar rods are Chinese forgings, just like Eagle and MANY others).
The factory rods are forged powdered metal. Not the strongest forging process, but forged regardless. The factory gen 4 rotating assembly has been ~1600 horsepower.
If you're wanting to forge everything, find a sponsor that can piece you together a rotating assembly for a competitive price.
That way you end up with parts that work and for a price that'll be cheaper than picking them yourself.

Biggest thing to consider when going with an LS turbo setup is the "Stop overthinking it" approach.
My first (personal) turbo LS engine made 4 digits at the flywheel on a stock engine I bought from a scrapyard and a refurb Borg Warner turbo from ebay. Replaced almost nothing.
I was only shooting for 600-700, but have put bus lengths on top of bus lengths on $10k N/A stroker LS engines making 700+ horsepower.

Basically, any forged LS engine regardless of displacement (because turbo's could care less about cubes) is going to be able to make 1200 horsepower.
Do what you think you need to for reliability, just remember not everything is necessary.

I would personally start with the cheapest setup I could and work up from there. Don't spend a ton of money on a learning experience, or it'll be one you 'learned from your mistakes' on.

 

Junkyard block + forged rotating assembly package deal then. I like the sound of that.