Trying to build a street/strip truck

3000lb race weight vehicle 98 Vortec 5700 L31 engine (factory longblock) airgap single plane and carb t-70 turbo. 600hp max

Currently have a built th350, 3000 stall converter TCI super street fighter with the anti-balloon nitrous plate.

I'd like to run a 3.08 or a 2.73 gear. But I'm afraid I'd smoke the converter if I run that low of a gear.

Any suggestions on a converter that will take the load of a 2.73 gear @ 600 HP levels?

Do you think the th350 will hold the pwr with a 3000lb car? Or do you suggest moving up to a th400?

 

A turbo 400 would handle the power with ease with a few upgrades and is much more durable than a turbo 350,but the downside is that the 400 will lose more HP .A turbo 350 should be able to get the job done.How tall of a tire do you plan on using?something in the 3.25 range would be better for the street.your running a 5.7(350) with a t-70?thats kinda small for an engine of that size a 76 would be much better suited.the 76 would get you to your HP goal with room to grow.the t70 is gonna be pushed to the limit.

 

600 is the max I'd be making. Not trying to make a 9 second car here. I'll probably leav eit down at the 500 hp levels for street driving. SO I think the 70 is a good choice and will spool quickly.It's also a bone stock 5.7 and is mainly a street car. Running a 9" rear with min spool and a 28" tire. I want to shift at 5400. I want 2.73's because it will put me around 45 @1500 rpm. Oddly enough A buddy of mine with my 2600lb 500hp boosted rx-7 went from a 3.42 to a 2.73 and actually picked up MPH/e.t. in his 1/4 times. Believe this is due to the extra load put on the turbo... And the driveability is awesome.

 

if you want either to use 2.73s or 3.08s and its mainly for the street your better off with the 3.08s,you would be at 2200-2300 at 60mph
which isnt turning much rpm at all.why do you want to shift at 54oo rpm?why not 6000rpm your leaving a few tenths on the table there?if your worried about mileage you could get an overdrive trans like a 700r4.

 

Well thats the factory redline. And I've found in the past that by turn up the boost and keeping the rpms down my motors seem to live long happy lives. I figure I can easily make 500-600hp at 5400rpm. Why both reving it higher if I don't have to? I shift my little buick 3.8 at 5000 and have run up to 30 psi with no issues on my 68mm.

I'm pretty set on 2.73's just worried about the converter and th350 holding up.