try this reading some info on this thread:
http://www.skylinesaustralia.com/forums/Ga...al-t134033.html
and this:
http://www.skylinesaustralia.com/forums/Gt...et-t169915.html
thing is most of us use a single 3082R on our engines, usually an RB20 or RB25 (2.0L and 2.5L respectively). What you're suggesting is using two of them on an engine with a displacement more than twice that. Now, turbo's are spooled by exhaust gasses, so assuming your engine burns twice the amount of fuel as ours, it'd make twice the amount of exhaust, which means it should spool two of those about the same as one of those turbo's on a skyline. Its only my guesstimation though. You'd really have to ask someone who works with turbo V8's for a definitive answer. I'd look towards forums in the US, specifically turbo corvette forums.