yes, theres prolly alota custom stuff, no doubt. i just never agreed with buying crate engines if your building a custom ride. they are always detuned (smaller cam, etc etc).
darton sleeved lsx block, siamese bores, to whatever bore this particular engine is (~4.125, whatever) $3,000
forged h-beams with arp 2000 - $700
custom diamond pistons - $1000
forged stroker crank - $1200
bearings - $500
fasteners - $500
gaskets - $400
custom cam - $400
timing chain - $200
PRs - $100
AFR/ETP/LS7 heads (complete)-~$2400 - $3000 <–(if ur goin really nuts and really biggg)
machine work (keep in mind, block is already machined, so only balancing and honing is required) $250
this is a rough estimate. some parts may be more, some are def less. this is not including transferable parts, assuming you have a lsx based engine.
it would be roughly $12,650
now add parts assuming you would build it as a (crate)
rockers - ~$500 (really dunno what stockers would cost)
lifters - ~$500 (same thing)
dry sump system - ? (i have no idea, never looked into one)
so that would be ~$14,000 - $15,000 + oiling for complete crate.
then add accessories, intake, TB (swap from what you got)
with this CUSTOM engine, you will make much MUCH MUCH more power. the parts will be able to handle much more power, and it will all be tailored to your style. add some nitrous ontop of it…and say goodbye
now of course this isnt including labor, but thats a nice benefit to learning how to build engines 
fyi, guys doing extreme all motor LSx builds with 427+ (454…) are making well over 600rwhp. NA. that is rediculous. add some nitrous to that, and think of the possibilities.