Hey guys I'm a new memeber but have been lurking here on occasion.
My first vechile was a 1989 Camaro RS V6 Auto that my Father, Grandfather, Unlce, and I painted one summer.

I now drive an 06 Cobalt SS S/C LSJ Manual and have a friend with a 98 Trans Am LS1 Auto.

We have a 400 SBC his father accuired to put in a car years ago but never did and doesn't want to mess with it so he's letting us have it. It's been sealed for years and when we get a chance will get the cast numbers to see if it's a 2 bolt or 4 bolt and what it came out of.

We plan to swap this engine into a 3rd gen z-28 or Iroc-Z between the years of 87-92. The engine will stay carbed. We're wanting to make serious power and plan on doing a twin turbo setup. This project is going to take at least two years. We want it done right .

So heres the questions.

What kinda compression do we want to look at for a twin turbo setup?

What kinda pistons and rods are recommened?

Heads?

This will be mated to either a TH-350 or a TH-400 with a 4k stall hooked to a 12 bolt rear.

Any suggestions and advice is highly appreciated!!!

 

Welcome aboard thirdgen.org

Get the casting numbers, but that won't tell you if it's 2 or 4 bolt, or what it came out of (although that doesn't really matter). Pull the pan and look at the main caps - that will tell you if it's 2 or 4 bolt.

I wouldn't advise turbo with a factory block, especially if it's 4 bolt. You can make serious NA power, though.

Fast Burns, AFR, Brodix, World - the choices are many.

 

Thanks!!!

So why no turbo on factory block?

Is thier anything I need to be aware of when getting ready to build this?

Again thanks!

 

Aftermarket blocks are substantially stronger than a factory block.

You will need a massive budget to do it right.

 

Our budget is going on 6000 dolars and we already have the engine for free.
The car is a later deal which will be funded on a seperate budget of about 4000 dollars.

 

$6000 is reasonable for a NA 400 with a free engine.

It's about half what you should figure for a twin turbo 400. About all you'll get from a free 400 for that project is a fit-check article.

 

Thanks for the info everyone!

Quick question what do you mean by fit-check article?

The Twin Turbo is two T3/T4 Hybrids turbos and come with everything needed to hook it up including the wastegate, intercooler, piping, and connectors for a SBC engine and we're getting it for round 800 bucks before shipping so bout 1000 to get it to our door.

 

Where did you find a kit for so cheap? Are they no-name cheapo turbo's? I'm looking for a kit similar cause I can't find a big single for under $1200...

 

Something to bolt into the car so you can make sure everything fits before you put in the "real" engine.

 

so i'm curious, what would be the harm in doing a twin turbo setup on a 400? so long as you have a 4 bolt main, forged internals, properly balanced rotating assembly, and a cam for forced induction there shouldn't be any problems with the bottom end holding up. yes, i understand that an after market block is stronger, and maybe lighter if you go aluminum, but would there really be an issue with anything?

 

Factory 400 blocks have thin and inconsistent cylinder walls. Factory 4-bolt blocks are weak in the main bearing web. Neither situation is a good way to start with a twin turbo set-up.

 

yeah if ure building a powerful 400 then u really want the 2 bolt. i say sell the 400 buy a 350 stroke it to a 383 and spray some nitrous for 6k u can build a pretty stout 383. stay away from that cheap turbo kit ull be just thowing your money down the drain. turbos spin at super high rpms and and have all that heat they are not something u choose by the cheapest option.

 

Nothing beats a twin turbo V8.

 

yeah but nothing beats the carnage of a poorly prepared twin turbo v8 setup either...well actually thats not true but u get the idea