Turbo sizing?

[69restomod]

Hey guys just bought a 6.0 lq4 and planning on doing a full motor build maybe using the factory 317s or switching to ls3 heads haven't decided yet and doing a single or twin turbo setup, looking for some advice on sizing thinking of a billet wheel s480 with a t4 exhaust housing and I will be running a 4l80e, I am open to all advice and information let me know what your running for headers or manifolds crossover tubing size what turbo what a/r and what kind of power numbers and drive ability your getting would also like to know cam specs! Thanks for the help guys! Pics would also be a great help

[BR3W CITY]

Power #'s, sizing, all that is just speculation until we nail down some some factors.

Built bottom end or no? Stock displacement?
Head choice will affect compression and flow characteristics, which will affect both cam choice and turbo sizing.
Single or twin? Its a preference and goals issue, but either can be made to work in most scenarios (twins cost more obv).

It sounds like your in the pre-beginning stages, and so you've gotta make the hard decision on goals, budget, timeframe. Otherwise our advice is like throwing darts at a wall and seeing what sticks.

[69restomod]

It's gonna have forged rods and Pistons good rod bolts gonna stick with the 317s now prolly have them ported to flow around 300cfm obviously upgraded valve springs good head gaskets, prolly run the Holley high ram or something comparable like edelbrock pro flow, looking for 700whp with daily driveable characteristics gonna run air conditioning and gonna go with a single turbo setup for now, I build double walled water cooled stainless stee turbo kits for high end race jetskis on the side so will either build headers or do a flipped manifold setup truck weighs 3800 pounds ? Let me know if you need more info

[BR3W CITY]

A Borg s400-series is semi popular in that range. Some guys go a little smaller with something like a 76mm, all the way up to 90mm if you don't mind waiting for the boost.
So something like the s475,s480 is going to get mentioned often. Going with a smaller A/R on a larger wheel helps dial back the lag if you choose to go with something "oversized".