Twin turbo firebird
 

I’m thinking of building a twin turbo firebird. I have a 1970 firebird that I was going to build a fairly radical NA engine for. The plan was to have a very fast car to drive on the street. But now I’ve been seeing a lot of turbo cars be faster and more street friendly.
I have an aluminum IAII block, 4.5 steel crank, Oliver 6.8 rods and 4.35 pistons with a 27 cc dish. The block is already bored for the pistons. For heads I have a set of wide port high ports or a set of 380 high ports. Both with 56 cc chambers. KRE told me they can redo the chamber up to 80 cc’s.
I’ve built many na Pontiacs, but never a turbo. Where should I start? I know headers are a problem. I can change most of the above parts if I need to.

Well, forging ahead I’ve ordered a 4 inch stroke scat crank from Butler. I’m going to order pistons Monday. I called a couple of guys about headers, but haven’t heard back. I’m not sure about turbo sizing or brand. Again I’ve called people and left messages but haven’t heard back. This may be a difficult build, but it’s going to happen.

Street Car that makes good power, hard to beat a correctly matched Twin Smaller Turbo Set-up. John Meany (Big Stuff 3 Owner.Dyno Guy) had a 1000 hp Corvette (SB Engine) that was about as violent as you would ever want on the street.

Going to the 4" crankshaft was a smart move.

You should have all the power you need or can put on the pavement.

Spend the money on Quality Turbos from Turbonetics/ Precision Turbo.

Tom V.

I guess I didn’t say in my original post all of my goals. We have a version of the top 10 list at my local 1/8 mile track that races on Thursday. The only real rules are street legal, tags and insurance, and no alteration of the rear wheel wells. They can also make us take them out on the street to prove they’re streetable. I’ll need to run high 4’s to be competitive. Most of these cars drive to the track, and are turbos. I already have a dedicated track car so I want to try this. John, I don’t know why but my notifications won’t open.

That's what I was afraid of.
(if you're talking of me)


I have twin turbos with wastegates still for sale.


johnta1@wallaceracing.com


:)

I don’t think those will be big enough for what I want to do John.

The Turbos John Wallace has for sale were Custom Built Turbos and each turbo was rated for 500 HP. How much hp above 1000 HP are you looking for?

I originally sold the Turbos and Wastegates to John, years ago, for his Dragster but he never installed them. Should still be brand new parts.

Tom V.

Your going to need 1,400 HP to run high 4's in the 1/8 mile! that probably 14-16 lbs of boost with a good flowing head a camshaft.


GTO George

The Turbos that Wallace has are nowhere near 1400 hp turbos.

Tom V.

High 4's with an uncut wheel well means small tire. If you can run a high 4 on the street with a small tire, you will be the king of the small tire in this country.
Last month at a small tire airport race, there was a 200,000.00+ car there with traction control all the bells and whistles, high 5 at best with small tire on the street.
Anyway, headers are a pita for Pontiac, If I was to do it over, I would built a log manifold. Good luck on the build keep us posted

Yea Logs

Your best bet will be to keep it simple. Short and sweet with the header. If you have the ability make your own. Keep the primarys between 1 3/4" to 1 7/8" and the collector needs no more then to be 2 1/2" . Anything more is just for show and will slow down spool..

If you can aford it. This turbo would be good for what you want to do when set up as twins IMO....

https://www.precisionturbo.net/Stree...PT6875-CEA/661

Good luck . Should be a fast car when all said and done.....

I’ve got a local guy who is going to build the headers,mounts and other tubing. High 4’s in the 1/8 mile. I talked to Travis Quillen last night, he says he retired, but recommended 2 precision 7675 and Holley FI. I need around 1400 HP.

Like I said! LOL!

GTO george

You can over 2000hp with the par of 6875s. And spool better..

Nice parts you have there going... You need a LIGHT & consistent car to reach your goals no matter what HP number they tell you! Small tire racing is tricky stuff !!

Personally I'd go with the more mass non wide port heads.. more durable clamping for sure.


Kris.

That’s what Travis said. Heads that flow around 320-330. I have a set of high port heads from SD that flow 380 that I’ll probably use.

The better heads the more HP you can make!

GTO George

I think the 76/75's will do well. Making the power that you'll need shouldn't be a problem with what you have. I'd start thinking of the driveline. Too deep of a SLR will give you trouble hooking up.

I’ve been racing this car for years. So it’s set up pretty well for NA. It has a turbo 400 with PTC converter and 373 gears. I’m thinking 2.10 first in the 400 and 308 or 323 in the rear. It has caltracs and single leaf springs, frame connectors and a roll cage. I know I’ll have to update the rollcage.

Twin
 

Ordered headers today. This will be his first set for a 1970 firebird.

For Pontiac engine? If so, very cool.

Yes. IA11 aluminum block with KRE HP heads.

What kind of price for the headers?


:)

800

That's a good price!


:)

So they already have them mocked up? Or did you have to send them any dimensions? Just wondering how involved you had to be in ordering these for a Pontiac. I want to get a set for my round ports... it would be awesome if its really that easy!!!

Good find!

SPEED SAFE, NICK

I’ve had to give him dimensions. He’s going to send me a set for test fit. I’m getting his first set for a firebird. He’s also making some for a GTO for test fit for another customer.

I wonder how close those would be to a first gen bird... Most the accessories mounted to the engine are in the same position... I wonder how different they would be...

NICK

I don’t know. My 69 is a full frame car.

I've got a 2.10 set for sale here if interested
http://forums.maxperformanceinc.com/...d.php?t=826291

Twin turbo
 

Turbos came today. Precision 7675.

Twin turbo
 

And an ft500

Twin turbo engine
 

Headers

Please post how these fit, or if you have to modify them to fit.

Thanks.

Holy crap those look good. Possible power steering interference. I went with a manual box(saved weight). Love to see a review of these. Please keep us posted.

I made that header design and it fit good in a 64 tempest..

Works good with boost too...

Heres 2 pics from when i was fitting it to the car..

Twin turbo
 

You’re one of the reasons I ordered the log style Charlie. When you said they made as much power and spooled quicker. They cleaned up the welds inside too.

Oh ok. You wont be sorry on this one. They did a good job on them ..

I migged mine so they look a little rougher then yours .

Good luck