LLY vs. LB7

01BlackZ71 · June 21, 2004

My family will probably be buying a new 2004 2500HD Duramax TODAY!

I need help on the engine code.

My Dad's 3 month old 2004 has the LB7 engine code for the Duramax Diesel.

The one that Mom's looking at today has the LLY engine code for the diesel.

What's the difference?

linda · June 21, 2004

well, i dont know the specifics, but since your in a hurry.........i believe the injectors on the "LLY" have been repositioned, and you also gain about 15 RWHP and about 80lb/FT of torque. Overall i believe the "LLY" is an upgrade over the "LB7". Good luck.

Chevyfreek · June 21, 2004

The LLY is the latest and great Dmax. That is the one you want. They have made some changes over the LB7 and the result is more HP and TQ as stated by linda. If the truck has the LB7 that is a good thing.

01BlackZ71 · June 21, 2004

Thanks. My mom ended up getting one with the LLY. I'll have to drive it and then compare it to dad's LB7 to see if I can tell a difference.

AUTOGUY · June 21, 2004

GM Started to put the LLY into their trucks in January of this year. I just bought a 2004 Sierra 2500HD CC/LB and it has the LLY. This is my first Diesel so I have nothing to compare it to. I do know the LB7 was 300/510 and the LLY is 310/590. I love mine. I traded a 2002 2500HD CC/LB with the 8.1 because it was killing me on gas bills. I am getting about 50% better mileage with the D-Max. Well worth it.

If you do a search on here or at www.gm-diesel.com someone has a listing of all the changes for the LLY. I think there are like 30 or 40 improvements over the LB7.

Time will tell if it is a better choice.