GMT800 Talk, chime in

[absinthminded]

Honestly, I don't know much about the 6.0L How much better is .7 liters? What else is different about the motor?

[Chris]

On the outside, nothing. On the inside you have 41 more cubic inches. Longer stroke so more torque, larger bore more HP. Your 5.3 is rated 285/325, my 6.0 is factory rated 345/385. I have the "High Output" version from the Silverado SS/Escalade/Vortec Max/05-07 Sierra Denali

[kstruckcountry]

Yours is an LQ9, right Chris?

[Chris]

Yes it is

[Badass69]

And the LQ4 is severely under-rated...... even in stock form in the Denali Suv's and such it was 325/330 HP and 370 lb ft versus the 300 HP and 360 lb ft in the HD's.... What's the difference? The HD's have power enrichment delay that the light duty trucks do not...... and...... the LQ4 in the HD is rated at 4400 rpm only whereas in the light duty stuff it was rated at 5200 rpm like the LQ9. Funny thing is in stock form an HD still revs to 5200 rpm WOT shifting lol. The LQ9 has a better tune, but not by a lot. Either engine properly tuned will make your 5.3 feel lethargic... even if it's tuned. 44 cubes, better heads and the 4" bore do that....

 

The only difference between an LQ4 and a LQ9 is flat top pistons in the 9 giving it the 10:1 compression ratio versus the 4 at 9.4:1. 04.5 and older LQ4's have weaker press fit pin rods... but 04 and a half model year and newer they have have the same heavy duty floating pin rod the 9 used.

 

Swapping a 5.3 for a 6 liter is a great investment no matter how you look at it.

 

I have both LQ4's and a LQ9...... my LQ9 makes a nice lawn ornament currently lol.

Edited September 18, 2013 by Notamember

[Chris]

The 04 up 9's have better connecting rods as well. I had an aggressively tuned 4.8 and I would never go back to anything under 6 liters again

[kstruckcountry]

Quit it guys, I have to wait for this motor to wear out!

[Chris]

No you don't. Just start saving now.

[Badass69]

The 04 up 9's have better connecting rods as well. I had an aggressively tuned 4.8 and I would never go back to anything under 6 liters again

 

LQ9's have had the heavy duty rod from the start excluding some early 2002 model ones. All LS engines ( 4.8-6.0) got the better rods mid year 2004.

 

We verified that with an early 2003 model LQ9 from an 03 Escalade that still had the small 10 mm head valley cover bolts on it ( although not gospel the 13 mm valley cover bolts generally indicate the floating pin rod) and it had the full floating pin rod. It was original too as the mid year shift of 2004 changed the head bolts from unequal length to equal length. This LQ9 had the old style unequal length head bolt arrangement.

 

Really guys call the rods LS2 rods which is honestly incorrect. The connecting rods existed 2 years before the LS2 even made it into production.

Edited September 18, 2013 by Notamember

[Chris]

I just know what I gathered over on silveradoss.com

[Badass69]

Quit it guys, I have to wait for this motor to wear out!

 

Bingo on what Chris said. 6 liters are cheap lol.

[Badass69]

I just know what I gathered over on silveradoss.com

 

Eh... I rip them apart myself to make sure lol. I had read both ways on the interwebz and then it was pretty well maintained on pt.net that the LQ9 had the rods all along.

 

That 03 with the old style unequal length head bolt block verified that.

[kstruckcountry]

Nothing is as cheap as keeping what I have. And judging by how good this motor runs with no tick and no oil consumption it will be good for at least another 100k.

 

Fortunately one of my friends is going to build a go fast truck, so helping with that will be fun.

[absinthminded]

Is there a lot of after mkt supoport for the LQ9? Headders, rods and pistons ect? I'f I was going to do it I would want to freshen it up and add boost. This is pretty much the only forum I look at concerning trucks. I'm not well versed.

[kstruckcountry]

Headers are the same IIRC?

 

And the LQ4 has lower compression than the 9 so I'm going to say it would be a better bet for boost.