whats the best way to tell them apart without pulling off the heads im going to look at one just want to be sure its a lq9 and not a lq4

 

LQ9 should be drive by wire. I'm pretty sure my dad's 99 with LQ4 is cable actuated. Lemme go check.

 

all the 03 ups had the dbw 99 to 02 had cable

 

Head casting #??

 

so what are the casting numbers on a lq9 i think there 317s

 

pretty sure this has been asked. Look at the pistons... bore scope

 

A Lot.
We should add some kind of search feature.
Really It took me 30-40 seconds to go to the Gm engine section click Search this forum. Type lq9 lq4 hit search and find the following thread.

https://www.performancetrucks.net/fo...hlight=lq9+lq4

Sarcasm of course. Letting you see how I found it helps others see how they too can find things.

 

Nope, 02 lq9 had the vette DBW.

You can limit it down pretty easily by checking if there is a spacer at end of the crank. This will be an LQ4. If there's no spacer, that narrows it down to either an LQ9 or an LQ4 out of a denali. Given that probability, and being told it was an lq9, I would be assured it indeed was an lq9.

 

The spacer was only on the 6.0 with the iron heads on it(99-early 00), once they got aluminum heads, they went with the shorter crank.. Pull a plug out and check the pistons, theres not a truly easy way to tell, unless you seen what it actually came out of..

 

only way to tell is to look at the pistons

LQ9 = flat top piston
LQ4 = dished piston