Turbo selection for my engine
 

OK I will give you some info

Its is a 470 bbc , burns e85,quickfuel carb solid roller valve train, dome pistons and 11.5-1 compression , msd 6A ignition on gutted hei. I run a final timing of 34deg. The engine make 525hp at the flywheel.
I have headers with t4 flanges on them. I want to put turbos on it.

From what I understand about forced air the cr raises with every pound of boost, so I will have to get some forget dished pistons to get my cr to about 8.50-1. I want to keep this motor streetable and my cruising rpm is 2200. I was looking at turbos on ebay
TO4E the item # 170535547007. Would two of them be big enough. I dont want the turbos to start working at 5000rpm. Am I mistakin to want them to start coming on at about 2500rpm, or so.
I will be switching to a mpfi from affordable fi. It supports turbos in the programming. That should make it a little easier on me.
This is where im at right now. Am I headed the right way any and all help is greatly appreciated.

this is untrue. BBC can take more boost.

i know a few guys running 11:1 pistons with a supercharger and no issues whatsoever.
dont follow the 4banger rule with a BBC. the motors can take MUCH more. believe me.

also, with a BBC it requires alot more air. so a small TD04 wont be enough. you will max out a small T25 or T28 stupidly fast. look for a bigger turbo. 10PSI on a T25 is not the same as 10PSI on a T28.

ok then how big of turbos will I need to go for a twin setup? I would dont want to use two but thats what my headers tell me I have to do.

Would a pair of gt45's be enough to run it?

gt45s are more then enough. those things flow a ---- ton of air.


ill do a bit of research for you, i got a few resources

Ok thanks now what numbers should I be looking for in the gt45's I see all these specs and I have no knowledge of turbocharging. The ones im looking at are

Compressor: Inlet = 4 3/16", Inducer = 68.7MM, Exducer = 97.8 MM, Trim = 69, A/R = 0.66, Intake (ID / OD) = 2.25" / 3.25"

Turbine: Outlet = 4", Turbo flange = T4, Downpipe flange = 3.5" V-band, Inducer = 87.4 MM, Exducer = 77 MM,Trim = 92, A/R = 1.05


These are huge compared to alot of what i seen online. I really need these??

sorry everyone you will have to try and bear with me untill I can figure some of this out.
DannyAE I appreciate the help.