I was wondering what would be better on my setup,my motor is going to be a built 346 ,right now i have a 60mm.96 backhoushing the guy from the turbo shop said that he can swap the 60mm to a 70mm and use the same back housing.96,but i wanted a t76 .96 but he told me to make my existing turbo that size it would be $400 more so i am leaning for the t70 what do you guys think my goal is to run 93octane on the street 10psi to 12psi and 600+rwhp I dont want to run out of air the 60mm is at full boost at 3000rpms
and tends to run out of air on the top end side, i want serious top end!!

 

Spend the $400 dollars, your car will pull harder at higher RPMs, thus giving you more MPH. I think the T76 is worth the money.

 

How will the 76 act with a .96 a/r on the back of the car? (anyone in the know... someone else was talking about this recently on another board I freq.)...

 

well no one has gone with a big daddy on the back of there so i think it might be worth a shot but there charge for the t76 is $800 total or the t70 for $400

 

if your goal is only ~600 rwhp, do the 70. i think the 76 is good to ~1100 hp, so thats without a doubt over kill.

 

any other imput

 

Careful with the .96 A/R in the back. Turbo's need heat, and due to the lack of it, STS's generally run smaller exhaust housings to compensate and create an adequate spool. I'd wait for STS experts to chime in on that. Regarding the 76, the 70 will do fine... But if you plan on going over 650 rwhp or so, the 76 will be worth it for the REALLY high hp.

 

GT76 with a .96 is on the back of my car!! I have a built 370 though. I start building boost in the mid 3k range, although I'm still tuning my VE table so I haven't run it into boost too much. What kind of cam and heads are you going to run? I would think though that the 70 would be enough for a 346, especially for a street setup.

 

i think a t70 for 600 and being a sts..there a guy on here that mad 600+ rwhp with the 67 but on race gas...soo boost will come on faster with the 70 and not to much lest hp's on the top end

 

Going to be a built engine?

I'd go for T76, you'll move more air with a cammed engine so you need more turbo.