Like Sas mentioned, twin turbo’s on the stock engine would be a waste.
The reason for twin turbo’s is to provide a high volume of air. The amount of air passing through and engine is directly proportionate to the horsepower.
To make room for that volume, you must start with 8:1 compression. The engine needs to be stroked to gain displacement and the rotating assembly needs to be forged with rods and pistons to match. The main bearings should be upgraded to 4 bolt. The heads should be replaced as well as the intake manifold. The camshaft of course needs to be replaced.
The engine needs a stand alone computer to deal with 3 bar MAP sensor and needed fuel management. You will probably need two or three fuel pumps depending on size to feed the monster at wide open throttle. The fuel injectors need to be sized for 80% duty cycle at full power. RC injectors have tables to figure this out.
The stock transmission will NOT work. You need a 4L80e trans with a few modifications, like optional input shaft and 3400 stall speed locking Torque Converter. A TCI Control unit will be needed for the transmission.
If you have the knowledge to tune your own computer and make it all work, you are all set except for what you want to do for “off road”.
If you drive sensibly on the street, the axles and differentials will hold up for a while. If you are going to turn loose this kind of power off road, the axles, wheels, differentials, u-joints etc, must all be upgraded.
Either way, it is also recommended to have safety hoops around drive shafts, so they don’t come up through the floor when the u-joints break.
For less money and headache, you could just order up the 720 hp big block GM engine along with a 4L80e trans. Normally aspirated with no screwing around.
This is the Banks Turbo system I am using. There is also a video showing them doing the dyno on the small block chev.
http://bankspower.com/products/show/267?app_id=85
http://bankspower.com/videos/show/20-twin-turbo-engine-dynod-at-1100-hp
Here is the site for the optional big block normally aspirated...........you might have to copy and paste to get there........
https://store.gmperformanceparts.com/store/SelectProd.do?prodId=7657&redir=true&manufacturer=GM&category=Engines&name=ZZ572/720R%20Deluxe%20&model=<!--12498827--
Here is the fuel injector site where you can figure out the size injector needed.
http://www.rceng.com/technical.aspx?UserID=1289940&SessionID=krt82JiKjffj1ZoxbJMA
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