RAM357

My dad and I are looking into doing LS swaps (with 4L60E auto trannies) into our 2004 and 2005 Unlimited TJs, and we're researching the various LS engines...

The 5.3s seem to be much easier and more common to find than just about any of the other LS engines...

We're thinkin that we're gonna want between 350 and 400 raw hp...

It looks like Gen III 5.3s typically have 285hp and Gen IV (LY5 and LMG) have 320hp...

What would it take realistically to get a 5.3 to 350-400 hp? Can that be done with easy/inexpensive mods such as a cam, ECM tuning, cool air, etc?

If this is reasonable some examples of the upgrades and expected hp results would be great!

Thanks,
Rob

NovaCain383

iTrader: (8)

Cam and Tune would be a good start.

bronx_peanut

The 5.3 crate motor from gmperformance parts they call the LS 327 makes 350 hp with a carb intake and a ls1 camshaft. If you went with something bigger you should be making more than that. Also get a good set of long tube headers. Here is an article that I found that Super Chevy made over 400 hp with a junkyard 5.3. http://www.superchevy.com/technical/...age/index.html

RacnJsn95

iTrader: (4)

I've read a couple articles that just swapping in an LS6 cam you will gain 30hp. They're pretty cheap to come by, as are the yellow valve springs for it.

RAM357

Thank you guys for the quick responses...

THe article at superchevy was very interesting. And the benefit from an LS6 cam is good to know.

Without making rediculous settings that damage MPG, etc... what is a realistic idea of the benefits of a good tune in terms of horsepower and torque?

jay7199

iTrader: (9)

always tune LS based motors, tuning is highly available for them and does alot for the car.

RAM357

I believe that having a good tune done can make a huge difference... just trying to get an idea of how much torque/benefit you might experience over a factory tune?

BTW... I live near Austin, TX... anyone know of a talented and honest tuner in this area?

Thanks,
Rob

hcb1700

iTrader: (9)

The LS6 cam and spring upgrade with a tune would be a great upgrade, and it will not hurt your gas mileage much. You can get a new set of LS6 springs from Lingenfelter for about $53.

RAM357

hcb1700,

Do you have a ballpark/gut feel for actual hp/torque change doing an LS6 cam and spring upgrade?

Not looking for exact... just realistic ballpark... what I should really expect to get out of that upgrade...

Thanks

bronx_peanut

Here is a Car Craft article about a 5.3 that is making the horsepower you are looking to get. http://www.carcraft.com/techarticles...ock/index.html

jay7199

iTrader: (9)

look up blacker on here, he knows his stuff.

bonecrrusher

iTrader: (1)

Isnt Texas Speed and Performance somewhere down there?