This may be the wrong forum, and if so I apologize and ask you to move it to the correct one.

I just spent the day with a family members LQ9. I'm wondering how to replicate it's performance with a '99 Vortec 5.7. I want the wife's Suburban to respond like an '02 6.0 LQ9.

What would be the most cost-effective way to achieve that? Eventually the 5.7 will have a problem and I can justify rebuilding/replacing it, and I'm wondering what the best way to go would be.

I'm asking the LS1 board because you guys are probably most familiar with the performance I'm asking about.

 

respond....as in...get up and go?

some basic performance mods should do the trick. things like a low restriction air intake, free flowing exhaust

it's possible something like new rear gears will give you the low end boost you want.

i know my dad's 03 silverado 6L has some great low end power...picks up nice to about 70...then drops off. i also know he's got 4.10 gears.


i guess i need some more clarification on what you mean


oh...and any of the mods i suggest...will hold over if you ever stroke it...you'd want those anyway...so why not get them now

 

I need to clarify- I have a '99 with the "Vortec" 5.7, and I want to know how to make it accelerate like an '03 with the 6.0 LQ9.

What's my most cost effective way to build the extra 100 - 125 horsepower, and will it pass emissions?

 

Nitrous and yes

 

the vortec is still the LSx based engine if i'm not mistaken. i don't think it is the old vortec style in the early 90s trucks.

but basically you should be able to just swap in a mild cam and heads package, along with the associated bolt on upgrades.

if done correctly and tuned properly...emissions shouldn't be an issue.

something like the tr224 cam and a set of small runner heads like the Dart 205s should make 400rwhp and a nice fat torque curve

 

Vortec 5.7L is not LSx-based. The only 5.7L LSx has been in the Corvette/GTO/F-body cars.

Truck LSx engines were/are 4.8/5.3/6.0/6.2.

 

Yeah- it's NOT (unfortunately) an LSx motor. And, no nitrous. This is the wife's vehicle.

You think I could do it with a cam and a tune? Or would I have to have the heads worked?

And, if I'm having the heads worked, why not put a 383 into it? Do you think the extra displacement would offset the LSx advantages?

 

If moneys not an option and you're not in a place thats too strict on emissions then a 383 with heads/cam and a tune would be the best way, you could easily get it up to 400hp or higher with that. however you're looking ~ 10k easy
a small blower with a good tune MIGHT be the cheapest way to accomplish what you want but your tune better be dead on and you cant run too much boost or else youl'l end up killing the engine prematurely. This really oughta be in general tech btw and not LS1 engine tech.

 

Moved to General Tech per the OP's request.

 

cam, headers, 4.10 gears and a tune should give it the desired pep