Is it an lq9? Its a 2006 2500hd

 

Probably LQ4.

LQ9 came in Escalade & Denali type vehicles.

 

Stick a bore scope in the spark plug hole. Flat top = LQ9, dish = LQ4.

 

Assuming that you're asking about a 6.0, it should be an LQ4. LQ9 motors came in hot rod pickups and required premium fuel. Work trucks and vans got LQ4's.

Like said above the flat top or dish piston will tell you which you have. Dish is LQ4 flat is LQ9

 

Dome is LQ4? That would increase compression over a flat. DISH would make it lower, which LQ4 is. Come on Pooter, you know this stuff! lol

 

If it's still in the truck or you know what truck it came from you can just check the rpo codes. Otherwise do what they said above and check the piston.

 

Oops, typing while drinking can be dangerous.

 

Uh-oh, officer, I believe I observed someone TUI... suppress him!!

 

like pooter said if its a 2500hd with a 6.0 it will be a Lq4 with 8th digit of the vin being a U

 

LOL stop resisting!