00fxd

Hi all
I am looking to purchase what is said to be a 2003 LQ9 on the floor. Can any one tell me how to determine physically if it's an lq4 or a 9?
Thanks, Frank

69camaross

iTrader: (4)

Run the VIN from it. If it comes back as being pulled from a Cadillac Escalade it's an LQ9. If it's from a Chevy or GMC its probably a LQ4 (LQ4 to LQ9 build ratio is like 20 to 1). The main difference between them is the compression ratio (rod & piston). 360hp LQ4, 400hp LQ9. If its a 01 or newer LQ4 it will also have aluminum heads. The 07+ LQ4s have the better flowing heads. Hope this helps.

00fxd

Thanks 69, I don't have the vin - it has been on the shop floor for 4 years. I can get a # stamped in the engine.

adam1803

iTrader: (65)

The only way to tell for sure is to take a look at the pistons, if you have a borescope available you can just look down the spark plug hole. The pistons will have a slight dish to them.

00fxd

Thanks fellas, that helps...

69camaross

iTrader: (4)

There should be a bar code with the VIN somewhere on the engine.

OUTLWZ

04+ LQ4's and LQ9's had the same rods and rod bolts and coated pistons. They made the LQ4 a little stronger.

LQ4 block #'s are-12575147 or 12575148

LQ9 block #'s are-12499467

Hope this helps..

00fxd

Thanks again '69, I will have him look for the sticker - I think I can see it in one of the pics I have.

OUTLWZ are those casting #'s on the block or part #s from the parts catalog?