I currently have a Precision T63 that was sized for my 5.4 build, Just thinking of switching to Twin turbos and was wondering what size I should use.

 

honestly I'd pick up another t-63. They're rated for 750hp worth of air at 30psi which means about a third of that plus a bit at 15psi per head unit. If you're looking to get about 600hp from it (a good number for a turbo 5.4) at moderate boost, then twin t63's would be just about right.

If you're worried about turbo lag then drop down to a t-61. You'll have boost instantly with the 61 and just a hair of spool up time on the 63.

 

My exhaust side would have to be reworked it has .96AR P-trim from Precision. Which is way to big for the 5.4 in a twin application. I wonder how much they'd charge to rework the exhaust side.

 

it's less than a new turbo that's for sure.

EDIT: You know what kind of power you're staring at right? That's gunna be a monster even on low boost. What are you going to do for a tranny? I'd seriously make sure to include a tko or t56 in the build. You guys are makin me so proud... proud.