408" with 6-8 lbs boost

Well set up turbo can make all kinds of torque, when the turbo start to spool.
Remember when you add boost you don't necessarily gain any rpm, you just make a butt load more in that running range.
Example a 340 built to make power from 3-6000 rpm it will still make power in that rpm just a lot more power and torque in that range.