This is a great site for pics on DIY. This guy uses a T70 on a Lexus 4lt V8... though smaller than your motor it gives you a good idea anyway.
That size turbo would be still awesome on your 400ci

http://www.lextreme.com/st.html

T04 would be way too small unless upgraded...Two would be o/k though..
Check here for turbo size...
http://www.turbofast.com.au/javacalc.html

And here for good turbo prices...
http://www.gcg.com.au/default_800x600.htm

thanks heaps for the help and direction for information, it has made my life a tad bit easier.

T4's come in to many size combinations, there was or still is a XC Cobra 351C fitted with a single T4, it mounted over the top of the engine near the firewall, it was in a few magazines in the early nineties, a Melbourne turbo specialist was the owner and it supposedly produced 600hp at the flywheel, and got a hiding from testing all the time.

Does anyone remember this car? I think it was AVO owned?

nice!! would be an interesting car to drive. i am pretty set on the t76 as it is HUUUGE and seems to be a popular choice for similiar sized engines. next step trying to find one, without having to sell my arm and leg. i have figured out the exhaust side of things and i think i have that side pretty much down pat, its the dump pipe that i think will be giving me the issues, im just not sure where to plumb it?

ok i have been looking around the net trying to find local (australian) companies that can sell me a T 76 turbo. do you guys know of any sites/ businesses that i can email to get some quotes on purchasing one of these babies.

uuuuuum, you do know that 400m was a model of engine dont you?

It was after the clevo and windsors, they put the letter M on the end. It means nothing though!

The engine will need some changes done to run forced induction!! First off they have a tendancy to ping even N/a..The problem is the pistons sit way too far down bore!! Leaving some flame behind from last exhaust stroke, igniting intake charge..The cheap fix is to fit over size gudgeon pins and raise piston height..Yes it will raise comp but if there is no quench or too much between head and piston detonation IS an issue..The are low comp engines anyway..
A T70 can be made up from a T04...Just fit big housing on turbine side as big engines need exhaust flow at higher rpm or it will choke real bad..
Cruse the truck wreckers..Get a turbo off a Scania or latter model Mitsi diesel 7 + ltr...
New you could use the GT45....