Not including junkyard turbo builds, it always seems to be that when turbo'ing v8 motors to go for maximum power, people tend to be to conservative on the turbo size. I know the turbo manufactures put the HP ranges on the turbos and sometimes it looks like a certain turbo would be way too big, but in real world, you have to really oversize the turbo to get big power results.
I agree the cam doesn't have to be overly aggressive either, more lift is good though.
I got most of my turbocharging experience in Japan, whats considered right for a motor over there is seen as gargantuan over here. Their favorite turbo for 2-3 litre class motors are turbos in the single 72-76mm range even for street car use(500-800 rwhp, pump gas). Add some more performance parts like flat shift transmissions, built motors etc and the turbo's go bigger yet. I run a 81mm turbo on a street car with a 2 litre motor.
I've watched a lot of turbo v8 builds on youtube and the power always seems kinda low when people are turbocharging 5 litre or bigger motors. I want to try a 400 B engine turbo project, but I don't really have any kind of chassis to put in.. I have a motor and pile of turbos laying around..
If I applied the Japanese tuning shop methods to it, it would be like this:
-shortest runner turbo manifolds possible(long manifolds kill power and increase spool time)
-Largest intercooler piping and intercooler I could get my hands on( this doesn't make lag, it cuts lag, it lets the engine breath to spool the turbo)
-port fuel injection with staged injection
-largest throttle body possible
-run twin 80mm minumum
-build engine to rev to 7000 rpm
-tall rear end gear
-6 spd close ratio transmission with flat shifting or 5 spd auto.
-best breathing heads possible
-Size the turbine so the W/G is wide open at target boost.
-low compression ratio around 8:1 (increased Mass flow rate, engine acts bigger than a higher compression motor)
I should start looking for a good D-150 to do the 400 build on with twin GT45's.. Maybe after I move shop to somewhere else.