Custom turbo
Custom turbo
I think you could get away with a 55-60mm turbine and that might be more ideal for you to spool as fast as possible. An s200 with a VNT housing I would prefer 65-70mm turbine wheel with a 0.8-0.9 A/R. Good spool and good flow on the top end.
The later version of the GT3782V (Ford 6.0 05-07) has a slightly smaller turbine than earlier versions, but the +72mm turbine and 55-60lb/min compressor are a bit big for only 400hp. It would work, but it would be sacrifcing spool for a top end that you cant actually use. However, considering you can get a brand new genuine Garrett turbo for $750 you're getting a lot of turbo for your money.