So.jerZ-28

iTrader: (20)

I've got a sweet deal on a pair turbonetic ballbearing type 76's w/.96ar

thinking about putting them on a 408c.i. fbody w/ viper spec t56


what you guy's think h.p. will be on a conservative tune/boost level (850+)

and how "streetable" with this be.
(yeah i know t400 is the way to go but I can't give up rowing gears)

note: twin 76's will go in a weekend full street trim car , I want to make sure it won't take me til like 100mph to make full boost!!!

camarols1

iTrader: (17)

As a point of reference, I am only 6.0L with journal bearing twin 66's with a .86 AR and I have full boost just over 4k. This is with a TH400 though.
Keep in mind I built mine to be a little soft off the bottom intentionally since it is a small tire setup and I wanted to be able to get some traction on the street.
The Tbrake allows me to build 5psi in less than a second at only 3,300rpm so it worked out to deliver power exactly like I wanted it to.

The power will be easy to make with that much displacement and the size of the turbos, but I am sure with the proper cam you could have great manners too.
Have a reputable shop like VA Speed spec a cam for your goals, and you will be able to spool those 76's way sooner than 100mph lol !!!

I had to beat this theory into a friend of mine that has a single 74mm on a SBC that went from a 218/225 112lsa off the shelf cam to a 230/232 115lsa ground specifically for his goals and the car picked up power EVERYWHERE, spools faster, and idles better. The "nicer" cam made the car pick up almost 5mph in the 1/4 mile !!!
A turbo setup will make power with ANY cam, but the proper cam will give the engine the power AND manners that you desire.

Just my $.02

Jim

So.jerZ-28

iTrader: (20)

cam is a 224/228 581/585 @ 116

98Z28CobraKiller

iTrader: (17)

That cam will sound and drive stock in a 408. Those exhaust housings are going to be lazy, specially with a stick. They will need an auto with a big stall (5500+ ish) to work well IMO.

RAACCR

Swap out the turbine housings for .68 a/r's for better response. 4 bolt heads? You'll push water long before you run out of turbos.

ssinister550

iTrader: (8)

If your only wanting ~850 hp one of those turbos will do the job through the manual. If your gonna use both get some .81 A/R housings (depending on the turbine wheel, I assume its a p-trim) and shoot for ~1200 hp. For a manual trans street car you'll have more of a usable power curve IMHO with a single 76 or a set of smaller turbos. But If you just want to go crazy run both turbos and shoot for at least ~1200, that setup with a manual isn't going to have alot of power under the curve but once the power comes in its gonna get nasty! good luck!

ssinister550

iTrader: (8)

btw everything is streetable depending on what your definition of streetable is. I know guys with 8 second cars that cruise around on the street with the 'chute hangin off the back lol

TrippyJoey

iTrader: (1)

If you want to handle all that power in a 6 speed you could go on the safe side and send your T56 to get converted into Tranzilla specifications. Sent you a pM with more information.

98Z28CobraKiller

iTrader: (17)

LOL @ clever name for expensive broken tranny.

So.jerZ-28

iTrader: (20)

i was thinking .68's would be better. I don't know, was pondering the idea.

I have a twin 67 setup on the car right now that i'm tryin to finish up. but was thinkin about the twin 76's........who doesn't like more h.p.?

camarols1

iTrader: (17)

+1 LOL...

PM Tiago about all the time and money he spent trying to make big power and have a reliable manual transmission with real track time on it.
BIG power and a 6-speed do not go well together unless you are going to run street tires and have no traction. At that point you might as well run much less power because there is no difference between 500hp and 1,500hp if the tires are spinning.

Revise the combo to have less power OR convert to an auto and you will have a happier end result with less wasted $$$

So.jerZ-28

iTrader: (20)

sounds like I'll be sticking wit the 67's that are on it !!!!

98Z28CobraKiller

iTrader: (17)

I think that with a stick, you are better off where you are. What I meant by my previous post is what CamaroLS1 said. A truly streetable T56 will not live for long at 800+ rwhp. Doesn't matter what "level" it is or what cool marketing name it has.

So.jerZ-28

iTrader: (20)

gotcha..... the trans will have a larger/billet mainshaft along all shift forks being steel, upgraded synchos,pads,gears & such.

I am only gonna run 12/13lbs on the street and I'll push it to 18-20 @ the track via a progressive controller.
I went with 1.05 housings to try and help the twin 67's not hit so hard & cause too much abuse on the drivetrain.

thanks for the heads up & info though!!!

1fast bird

iTrader: (22)

I'm running a 402 with twin tc76's with .96 housings and they are a bit laggy. That is through a th400. I wouldn't wanna try it through a 6-speed. Sure you can get alot of power with them but in the higher rpm's. Would not be great on the street. Just my $.02

So.jerZ-28

iTrader: (20)

what do you guys think of the twin t4 67's w/ 1.05's?

smaller turbos and I figure the 408 would be plenty to push them.

1fast bird

iTrader: (22)

For street I think you want smaller housings for quicker spool. Even with the 67's a 1.05 is gonna be laggy. .81's would be about perfect I would think. Better to ask Forced Inductions what is a good setup for your needs.

crashly

76's with a .81 a/r housing...is my pick
make sure you got a f1 - 68 turbine in those wizzers...