The main difference is the pistons. LQ4s are dished for low compression (9.5?) LQ9s are flat top for high compression (10.5?). On earlier models the rods were also different, with the LQ9s getting stronger rods. However, I have read that later models use the same rods for both motors.

 

so which engine is the aluminum lq9?

 

Doesn't exist, all LQ9's are cast iron block/aluminum head. The aluminum 6.0L is an LS2.

 

Be sure not to get a 6.0 from a 99-00...those are the ones with the longer crank and iron heads and are not a direct bolt in to a 4L60E. Make sure whatever you get is from an 01 and up.

 

I bought one this morning. Lq9 from an 02 Escalade with all accessories. The guy said something about a spacer so that it would bolt up to the 4l60e. I don't know whether he said I would have to use one off of my 5.3 or take one off of the 6.0. I haven't heard of this before. Anybody know if he is right?

 

Remove spacer and use flexplate from 5.3

 

my vmax came with a aluminum block

 

That is a very good point. The L76 is an aluminum block. I stand corrected.

 

So is the L76 like an alluminum block LQ9 or something totally different? What's the HP rating on the L76?

 

with a 00 Lq4 since it has the longer crank, can you put in a crank from a 03 LQ9 or is there a simpler way