Whats the difrance in the LQ4 and LQ9 think its nine... how can u tell the dif. witch one is better

 

did you use the search??? This has been explained before
LQ9 flat top piston, LQ4 has valve relief piston
I believe the LQ9 has higher compression

someone will chime in and correct me if im wrong

 

lq4 is low compression.... the only way to tell is pull a plug and look at the piston one is dished!
which one is better???
Well it depends on what you are planning for!
lq4 lower compression better for forced induction and such.
lq9 better for n/a applications and nitrous is good on either haha! but the lq9 (if both are left stock) is a better choice. Just decide what you are wanting to do?

 

In earlier years, the LQ9 had better connecting rods, in 05+ all 6.0 engines got the same LQ9 rods. So the earlier LQ4 will have the weaker rods (not that they're weak by any means, their just not as good as the later, LQ9 rods)