Is the compression the only difference between these two 6.0's? They are only 10hp different from the Denali and Escalade. Just wondering if anything else was different?

 

compression is the only difference I know about...LQ4=low compression...LQ9=high compression

 

Does this mean that an lq4 with programing will have the output of an LQ9? I thought that the LQ9 had flat tops and in it as well?

 

possibly, but not for the right reasons...I'm not sure how the compression is different (different piston top, different heads) ..... ok, after some research i found that the heads have different part #'s (12562317 for the LQ4 ('02 and up) and 12572317 for the LQ9) both have 210cc intake valves and 75cc exhaust and both have 71.06cc combustion chamber volume (including gasket).
so, the difference must be in piston shape
BTW cams are the same for both motors. LQ4 has been around since '00 and the LQ9 since '02.

 

lq9 has higher compression with flat top pistons and lq9 also has beefier rods

 

as far as most of us know, the only diffrence between
the LQ4 and the LQ9 is the pistons, LQ4 dish, LQ9 flat top and coated,
and the rods on the LQ9 is a little thicker when compaired to the LQ4.

 

I show that the rods are the same part number (12568734) for all model years.

 

Same crank too (part number 12559768 w/ a 3.662" stroke)

 

i'm pretty sure the LQ9 has the LS2 rods???

 

I think Grippys LQ4 had LS2 rods too.