http://www.gm.com/automotive/gmpower...ehicle/lq4.htm

GM lists the LQ4's peak outputs at 300hp@4400 / 360tq@4000 in the lower level vehicles (3/4 and 1 tons), but in the higher end model such as the Denali, they add another 15-25hp peaking at 5000rpm.

Is this just marketing trying to make the higher end (more expensive) models look better or are there actual differences between the motors?


http://www.gm.com/automotive/gmpower...ehicle/lq9.htm
The LQ9 is rated at 345hp@5200 / 380tq@4000
What is changed to get the extra power there? I notice the compression ratio is at 10.0:1 instead of the LQ4's 9.4:1. I've been told that these motors got the LS6 head. Is that true?

Has anybody actually dyno'd these motors to find out the actual power?

The reason I ask if because I'm considering the purchase of a Chevy Express with the LQ4.

 

no replies?

 

Sorry man, can't exactly help you. Don't know anything about LQ4's.

Now, if it was an LS1 I'd be all over your question

 

As far as I can tell the only difference between the LQ4 and the LQ9 is the pistons. The LQ4 has a dished piston and has a CR of 9.4 whereas the LQ9 has a flat top piston giving it a CR of 10.0. Both heads are supposedly the same heads as the LS6 except for a larger combustion chamber of 71.06cc.

Oh yeah, even among the LQ4 hp varies 25 and tq varies 10 among different models.